Considers the winter opening, operation, and maintenance of roads in Yellowstone National Park by the National Park Service. Hearing was held in Jackson, Wyo.

1. The problem. In propagation for summer planting the plant material generally will not be available in time to the growers. As the cause was not known, the question arose whether the reproducibility of the varieties was sufficient. | 2. Experimental procedure. The factors for reproducibility were ascertained. To this end an analysis was made of the factors determining the number of salable plants. This investigation consisted of three parts, which can be summarized as follows. | 3. Number of salable plants per mother plant. As the number of rooted runners increases, more runner plants per mother plant are formed (Tables I, p. 14, and 3, p. 16). | The optimum temperature for the growth of the sprout of a runner plant is higher than the temperature at which the propagation is done in the Netherlands (Fig. 3, p. 21, and 4, p. 22). The optimum temperature for the development of the root initials falls within this range (Table 5, p. 25). As for the establishment of strawberry plantations preference is given to plants with a not too heavy sprout, the temperature in the Netherlands is generally favourable for a rapid production of salable plants. Under good cultural conditions more salable plants are formed as the total number of runner plants formed becomes larger (Fig. 6, p. 26). | The number of rooted runners increases as the total number of runners formed is increased (Fig. 7, p. 28). | Therefore the number of salable plants formed by a mother plant is determined by the total number of runners formed, on the basis of the following considerations:1) number of runners ->number of rooted runnersnumber of rooted runners2) number of rooted runners ->number of runner plantsnumber of runner plants3) number of runner plants ->number of salable plants. | An exception is the variety Senga Sengana. It forms many runners, but the number of salable plants per mother plant is comparatively low, because only few plants per runner are formed (Table 3, p. 16). This is caused by:a. The phenomenon that in many runners at the base of the second or third runner plant a side crown is formed instead of a runner, giving rise to a runner plant consisting of two crowns (Fig. I, p. 17), which only starts to form runners after a certain lapse of time. The occurrence of this Phenomenon is associated with the rooting of the runner plants (Fig. 2, p. 18) and the growth of the mother plant.b. The low number of rooted runners compared with the total number of runners during the occurrence of the phenomenon mentioned above (Fig. 7, second observation, p. 28).By increasing the number of mother plants, the production of runners and consequently of salable plants per surface unit could be accelerated, permitting to lift the plants earlier. With Talisman this was the case both when the number of rows and the number of plants in the row were increased, with Cambridge Vigour only when the number of rows was increased (Table 6, p. 31).On the propagation fields plant spacings are too wide for the rapid production of a large number of salable plants per surface unit. This is one of the causes that the plant material will not be available in time to the growers. | 4. Number of runners per mother plant. Vigorous growth of the mother plant is an essential condition for the formation of a large number of runners (Tables 7, p. 34, 8, p. 35, 9, p. 36, and 10, p. 37). The higher the growth rate of a variety, the higher the number of runners formed. Hence, if many runners are to be formed, the mother plants have to be heavy in the spring (Tables 12, p. 41, and 13, p. 42). From the start heavy mother plants produce more runner plants (Table 14, p. 43). At the end of the propagation period the number of salable plants produced by heavy mother plants is considerably higher than that produced by light mother plants (Tables 15, p. 43, and 16, p. 44). Vigorous vegetative growth of the mother plant forms the basis for good reproducibility.As selection for productivity actually involves selection for vigour, this also lays the foundation for good reproducibility. The selection for reproducibility should therefore be directed towards continuous growth of the runners.On the propagation fields the mother plants are not heavy enough in the spring. As a result, the number of runners and consequently the number of salable plants formed per time unit is too small. In addition to the spacing being too wide, this accounts for the fact that sufficient salable plants will not be available in time on the propagation fields. | 5. Conditions for runner firmation. A strawberry plant starts to form runners when the daylength and the temperature have exceeded a certain value. Under a daylength of 16 hours there are varietal differences in the temperature at which runners are formed (Table 17, p. 50). These differences are not related to the distribution of the varieties. On the other hand, for northern varieties the daylength should be longer or the temperature higher than for southern varieties (Tables 18 and 19, p. 54/55).For successful cultivation of a variety in a certain region both the period of runner formation and that of flower initiation must have a certain duration. The length of both periods will mainly depend on the moment at which the transition from runner formation to flower initiation takes place. As this transition is determined by the daylength and the temperature and the varieties differ in their reaction to these factors a variety can only be grown successfully in regions where this transition occurs at such a time that the periods of runner formation and flower initiation are both long enough. Therefore, the distribution of a variety is limited.As the duration of runner formation within the geographic range of a variety is constant, the growth rate of the mother plant is the only factor which determines the number of runners formed. | 6. Final conclusion. The fact that the plant material does not become available in time is not the result of insufficient reproducibility of the varieties but of imperfections in the propagation technique.

1. The problem. In propagation for summer planting the plant material generally will not be available in time to the growers. As the cause was not known, the question arose whether the reproducibility of the varieties was sufficient.2. Experimental procedure. The factors for reproducibility were ascertained. To this end an analysis was made of the factors determining the number of salable plants. This investigation consisted of three parts, which can be summarized as follows.3. Number of salable plants per mother plant. As the number of rooted runners increases, more runner plants per mother plant are formed (Tables I, p. 14, and 3, p. 16).The optimum temperature for the growth of the sprout of a runner plant is higher than the temperature at which the propagation is done in the Netherlands (Fig. 3, p. 21, and 4, p. 22). The optimum temperature for the development of the root initials falls within this range (Table 5, p. 25). As for the establishment of strawberry plantations preference is given to plants with a not too heavy sprout, the temperature in the Netherlands is generally favourable for a rapid production of salable plants. Under good cultural conditions more salable plants are formed as the total number of runner plants formed becomes larger (Fig. 6, p. 26)The number of rooted runners increases as the total number of runners formed is increased (Fig. 7, p. 28).Therefore the number of salable plants formed by a mother plant is determined by the total number of runners formed, on the basis of the following considerations:1) number of runners ->number of rooted runners2) number of rooted runners ->number of runner plants3) number of runner plants ->number of salable plants.An exception is the variety Senga Sengana. It forms many runners, but the number of salable plants per mother plant is comparatively low, because only few plants per runner are formed (Table 3, p. 16). This is caused by:a. The phenomenon that in many runners at the base of the second or third runner plant a side crown is formed instead of a runner, giving rise to a runner plant consisting of two crowns (Fig. I, p. 17), which only starts to form runners after a certain lapse of time. The occurrence of this Phenomenon is associated with the rooting of the runner plants (Fig. 2, p. 18) and the growth of the mother plant.b. The low number of rooted runners compared with the total number of runners during the occurrence of the phenomenon mentioned above (Fig. 7, second observation, p. 28).By increasing the number of mother plants, the production of runners and consequently of salable plants per surface unit could be accelerated, permitting to lift the plants earlier. With Talisman this was the case both when the number of rows and the number of plants in the row were increased, with Cambridge Vigour only when the number of rows was increased (Table 6, p. 31).On the propagation fields plant spacings are too wide for the rapid production of a large number of salable plants per surface unit. This is one of the causes that the plant material will not be available in time to the growers.4. Number of runners per mother plant. Vigorous growth of the mother plant is an essential condition for the formation of a large number of runners (Tables 7, p. 34, 8, p. 35, 9, p. 36, and 10, p. 37). The higher the growth rate of a variety, the higher the number of runners formed. Hence, if many runners are to be formed, the mother plants have to be heavy in the spring (Tables 12, p. 41, and 13, p. 42). From the start heavy mother plants produce more runner plants (Table 14, p. 43). At the end of the propagation period the number of salable plants produced by heavy mother plants is considerably higher than that produced by light mother plants (Tables 15, p. 43, and 16, p. 44). Vigorous vegetative growth of the mother plant forms the basis for good reproducibility.As selection for productivity actually involves selection for vigour, this also lays the foundation for good reproducibility. The selection for reproducibility should therefore be directed towards continuous growth of the runners.On the propagation fields the mother plants are not heavy enough in the spring. As a result, the number of runners and consequently the number of salable plants formed per time unit is too small. In addition to the spacing being too wide, this accounts for the fact that sufficient salable plants will not be available in time on the propagation fields.5. Conditions for runner firmation. A strawberry plant starts to form runners when the daylength and the temperature have exceeded a certain value. Under a daylength of 16 hours there are varietal differences in the temperature at which runners are formed (Table 17, p. 50). These differences are not related to the distribution of the varieties. On the other hand, for northern varieties the daylength should be longer or the temperature higher than for southern varieties (Tables 18 and 19, p. 54/55).For successful cultivation of a variety in a certain region both the period of runner formation and that of flower initiation must have a certain duration. The length of both periods will mainly depend on the moment at which the transition from runner formation to flower initiation takes place. As this transition is determined by the daylength and the temperature and the varieties differ in their reaction to these factors a variety can only be grown successfully in regions where this transition occurs at such a time that the periods of runner formation and flower initiation are both long enough. Therefore, the distribution of a variety is limited.As the duration of runner formation within the geographic range of a variety is constant, the growth rate of the mother plant is the only factor which determines the number of runners formed.6. Final conclusion. The fact that the plant material does not become available in time is not the result of insufficient reproducibility of the varieties but of imperfections in the propagation technique.

1. The problem. In propagation for summer planting the plant material generally will not be available in time to the growers. As the cause was not known, the question arose whether the reproducibility of the varieties was sufficient.2. Experimental procedure. The factors for reproducibility were ascertained. To this end an analysis was made of the factors determining the number of salable plants. This investigation consisted of three parts, which can be summarized as follows.3. Number of salable plants per mother plant. As the number of rooted runners increases, more runner plants per mother plant are formed (Tables I, p. 14, and 3, p. 16).The optimum temperature for the growth of the sprout of a runner plant is higher than the temperature at which the propagation is done in the Netherlands (Fig. 3, p. 21, and 4, p. 22). The optimum temperature for the development of the root initials falls within this range (Table 5, p. 25). As for the establishment of strawberry plantations preference is given to plants with a not too heavy sprout, the temperature in the Netherlands is generally favourable for a rapid production of salable plants. Under good cultural conditions more salable plants are formed as the total number of runner plants formed becomes larger (Fig. 6, p. 26)The number of rooted runners increases as the total number of runners formed is increased (Fig. 7, p. 28).Therefore the number of salable plants formed by a mother plant is determined by the total number of runners formed, on the basis of the following considerations:1) number of runners ->number of rooted runners2) number of rooted runners ->number of runner plants3) number of runner plants ->number of salable plants.An exception is the variety Senga Sengana. It forms many runners, but the number of salable plants per mother plant is comparatively low, because only few plants per runner are formed (Table 3, p. 16). This is caused by:a. The phenomenon that in many runners at the base of the second or third runner plant a side crown is formed instead of a runner, giving rise to a runner plant consisting of two crowns (Fig. I, p. 17), which only starts to form runners after a certain lapse of time. The occurrence of this Phenomenon is associated with the rooting of the runner plants (Fig. 2, p. 18) and the growth of the mother plant.b. The low number of rooted runners compared with the total number of runners during the occurrence of the phenomenon mentioned above (Fig. 7, second observation, p. 28).By increasing the number of mother plants, the production of runners and consequently of salable plants per surface unit could be accelerated, permitting to lift the plants earlier. With Talisman this was the case both when the number of rows and the number of plants in the row were increased, with Cambridge Vigour only when the number of rows was increased (Table 6, p. 31).On the propagation fields plant spacings are too wide for the rapid production of a large number of salable plants per surface unit. This is one of the causes that the plant material will not be available in time to the growers.4. Number of runners per mother plant. Vigorous growth of the mother plant is an essential condition for the formation of a large number of runners (Tables 7, p. 34, 8, p. 35, 9, p. 36, and 10, p. 37). The higher the growth rate of a variety, the higher the number of runners formed. Hence, if many runners are to be formed, the mother plants have to be heavy in the spring (Tables 12, p. 41, and 13, p. 42). From the start heavy mother plants produce more runner plants (Table 14, p. 43). At the end of the propagation period the number of salable plants produced by heavy mother plants is considerably higher than that produced by light mother plants (Tables 15, p. 43, and 16, p. 44). Vigorous vegetative growth of the mother plant forms the basis for good reproducibility.As selection for productivity actually involves selection for vigour, this also lays the foundation for good reproducibility. The selection for reproducibility should therefore be directed towards continuous growth of the runners.On the propagation fields the mother plants are not heavy enough in the spring. As a result, the number of runners and consequently the number of salable plants formed per time unit is too small. In addition to the spacing being too wide, this accounts for the fact that sufficient salable plants will not be available in time on the propagation fields.5. Conditions for runner firmation. A strawberry plant starts to form runners when the daylength and the temperature have exceeded a certain value. Under a daylength of 16 hours there are varietal differences in the temperature at which runners are formed (Table 17, p. 50). These differences are not related to the distribution of the varieties. On the other hand, for northern varieties the daylength should be longer or the temperature higher than for southern varieties (Tables 18 and 19, p. 54/55).For successful cultivation of a variety in a certain region both the period of runner formation and that of flower initiation must have a certain duration. The length of both periods will mainly depend on the moment at which the transition from runner formation to flower initiation takes place. As this transition is determined by the daylength and the temperature and the varieties differ in their reaction to these factors a variety can only be grown successfully in regions where this transition occurs at such a time that the periods of runner formation and flower initiation are both long enough. Therefore, the distribution of a variety is limited.As the duration of runner formation within the geographic range of a variety is constant, the growth rate of the mother plant is the only factor which determines the number of runners formed.6. Final conclusion. The fact that the plant material does not become available in time is not the result of insufficient reproducibility of the varieties but of imperfections in the propagation technique.

ScopeWhen Freesias are planted throughout the year several problems arise. In some months, flowers are produced too rapidly and abundantly, with a corresponding loss in quality; in other months, flower production is limited and too slow. Simultaneously, there is a great variation in stem length, in number and shape of the flowers and in corm production.This study was undertaken to establish the effect of the two major inveronmental factors, temperature and light, on the characteristics mentioned, from the moment of planting to the harvest of the corms.ConclusionsFrom this study on the effect of temperature and light on the development of the Freesia plant, the following conclusions could be drawn:Effects of temperature in the range of 9-24°C:1. Sprouting of the corms was promoted by high temperature (experiments 1,4,19).2. The number of leaves was reduced (i.e., Rower initiation was promoted) by low temperature, and increased by high temperature, especially 21° and 24°C (experiments 1, 3, 4, 5, 19). There was a further reduction by a pretreatment at 5°C during 4 weeks (experiment 7). There was no specific effect of day or night temperature (experiment 4).3. The number of days to flowering reached a minimum at 18' (experiments 1, 3, 5, 19, 20; in experiment 4 the optimal temperature was 15°C and in experiment 2 it was 21°C. The night temperature was especially important (experiments 4, 5). There was a further reduction in the number of days to flowering by a pretreatment at 5°C for 3 or 4 weeks (experiment 7).4. The number of flowers in the main inflorescence was increased by high temperature (experiments 1-5, 19, 20; in experiment 3 there was a reduction at 24°C but it was also increased by a pretreatment at 5°C during 1 or 2 weeks (experiment 7).5. The number of lateral stems was reduced by high temperature; the greatest number was formed at 12°C (experiment 3) or 15°C (experiments 1, 2). A low night temperature was especially important (experiment 5).6. Stem length reached an optimum at 21 °C (experiments 1- 5, 19, 20); 24°C was unfavourable, especially in later stages (experiment 3). The effect of day temperature was much stronger than that of night temperature (experiments 4, 5). Stem length increased after a pretreatment at 5' during 1-2 weeks, but 4 weeks 5° led to stunted growth (experiment 7).7. Corm dry weight increased with the temperature (experiments 1, 2, 4, 19). The effect of day temperature was stronger than that of the night temperature (experiment 4, 5). Corm weight was reduced after a pretreatment at 5° during 3 or 4 weeks (experiment 7).8. The number of cormlets was decreased by high temperature (experiments 1-4, 19). A pretreatment of 1-2 weeks at 5°C increased it, but 4 weeks 5°C led to a decrease (experiment 7).Effects of the photoperiod in the range of 8 to 16 hrs:9. Leaf number was reduced (i.e. flower initiation was promoted) by short day (experiments 8, 12, 13, 19). The cultivar 'Sonata' was more responsive than 'Rijnveld's Golden Yellow' (experiment 15).10. The development of the inflorescence was strongly promoted in the early stages by short day (experiments 12, 13, 19) but later stages were promoted by long day, although not as strongly (experiments 11, 12).11. The number of flowers in the main inflorescence was reduced by long day (experiments 8, 10, 14), especially in the later stages (experiment 15). Long day also reduced the percentage of open flowers (experiments 9-12).12. The number of lateral stems decreased with the daylength (experiments 8-14) which was especially effective in later stages (experiment 15).13. There were no unequivocal effects of photoperiod on stem length experiments 9, 12, 15).14. Corm dry weight was proportional to daylength (experiments 8, 10, 12, 14), although it was sometimes lower again in the longest photoperiod (experiments 9, 11).15. The number of cormlets was greatest in short day (experiments 8-13).Effect of light intensity:16. Light intensity had little effect on the number of leaves (experiments 10, 13, 17), but low light intensity delayed flower initiation (experiments 13, 14), flower development (experiments 10, 13, 14, 17). It also reduced the number of flowers in the main inflorescence (experiments 13, 14, 17) and the precentage of open flowers (experiment 17). High light intensity increased the number of lateral stems (experiment 13). Stem length was usually slightly promoted by low light intensity (experiment 14, 17). Corm dry weight was proportional to light quantity (experiment 13, 14, 16, 17). The number of cormlets was reduced by low light intensity (experiment 10).Comparison of effects on light and temperature:17. Within the given ranges of these two factors the effect of temperature was usually greater than that of light. Only the number of lateral stems was determined primarily by the light conditions. As a rule, a higher temperature had a similar effect as a longer photoperiod (experiments 19, 20).Effect of planting date (experiment 21):18. The greatest number of leaves (and also the longest time to flower initiation) was found after planting in May and June, the smallest number of leaves after planting in February. The minimum number of days to flower initiation occurred after planting between November and January.19. The minimum number of days between planting and flowering occurred after planting in January and February; plants started in May took the longest time to flower.20. The number of flowers on the main inflorescence reached a maximum after planting in May and June and a minimum after planting between October and February.21. The number of lateral stems was high in plants started in June and low after planting in November and April.22. Stem length and plant height were greatest after planting between June and August and smallest after planting in February and March.23. Corm and cormlet dry weight were highest after planting in summer and low after planting in winter; the number of days between planting and harvest showed the opposite trend.Effect of planting density (experiment 21):24. In comparison to plants at a small distance, those at a wider distance were shorter, had more lateral stems and more flowers, a greater corm dry weight and more cormlets.25. The number of days to flowering was not affected by the planting density when the plants were started between November and March. Plants started between March and August flowered earlier when at a smaller distance; those started between September and November, however, flowered slightly earlier when at a greater distance.

ScopeWhen Freesias are planted throughout the year several problems arise. In some months, flowers are produced too rapidly and abundantly, with a corresponding loss in quality; in other months, flower production is limited and too slow. Simultaneously, there is a great variation in stem length, in number and shape of the flowers and in corm production.This study was undertaken to establish the effect of the two major inveronmental factors, temperature and light, on the characteristics mentioned, from the moment of planting to the harvest of the corms.ConclusionsFrom this study on the effect of temperature and light on the development of the Freesia plant, the following conclusions could be drawn:Effects of temperature in the range of 9-24°C:1. Sprouting of the corms was promoted by high temperature (experiments 1,4,19).2. The number of leaves was reduced (i.e., Rower initiation was promoted) by low temperature, and increased by high temperature, especially 21° and 24°C (experiments 1, 3, 4, 5, 19). There was a further reduction by a pretreatment at 5°C during 4 weeks (experiment 7). There was no specific effect of day or night temperature (experiment 4).3. The number of days to flowering reached a minimum at 18' (experiments 1, 3, 5, 19, 20; in experiment 4 the optimal temperature was 15°C and in experiment 2 it was 21°C. The night temperature was especially important (experiments 4, 5). There was a further reduction in the number of days to flowering by a pretreatment at 5°C for 3 or 4 weeks (experiment 7).4. The number of flowers in the main inflorescence was increased by high temperature (experiments 1-5, 19, 20; in experiment 3 there was a reduction at 24°C but it was also increased by a pretreatment at 5°C during 1 or 2 weeks (experiment 7).5. The number of lateral stems was reduced by high temperature; the greatest number was formed at 12°C (experiment 3) or 15°C (experiments 1, 2). A low night temperature was especially important (experiment 5).6. Stem length reached an optimum at 21 °C (experiments 1- 5, 19, 20); 24°C was unfavourable, especially in later stages (experiment 3). The effect of day temperature was much stronger than that of night temperature (experiments 4, 5). Stem length increased after a pretreatment at 5' during 1-2 weeks, but 4 weeks 5° led to stunted growth (experiment 7).7. Corm dry weight increased with the temperature (experiments 1, 2, 4, 19). The effect of day temperature was stronger than that of the night temperature (experiment 4, 5). Corm weight was reduced after a pretreatment at 5° during 3 or 4 weeks (experiment 7).8. The number of cormlets was decreased by high temperature (experiments 1-4, 19). A pretreatment of 1-2 weeks at 5°C increased it, but 4 weeks 5°C led to a decrease (experiment 7).Effects of the photoperiod in the range of 8 to 16 hrs:9. Leaf number was reduced (i.e. flower initiation was promoted) by short day (experiments 8, 12, 13, 19). The cultivar 'Sonata' was more responsive than 'Rijnveld's Golden Yellow' (experiment 15).10. The development of the inflorescence was strongly promoted in the early stages by short day (experiments 12, 13, 19) but later stages were promoted by long day, although not as strongly (experiments 11, 12).11. The number of flowers in the main inflorescence was reduced by long day (experiments 8, 10, 14), especially in the later stages (experiment 15). Long day also reduced the percentage of open flowers (experiments 9-12).12. The number of lateral stems decreased with the daylength (experiments 8-14) which was especially effective in later stages (experiment 15).13. There were no unequivocal effects of photoperiod on stem length experiments 9, 12, 15).14. Corm dry weight was proportional to daylength (experiments 8, 10, 12, 14), although it was sometimes lower again in the longest photoperiod (experiments 9, 11).15. The number of cormlets was greatest in short day (experiments 8-13).Effect of light intensity:16. Light intensity had little effect on the number of leaves (experiments 10, 13, 17), but low light intensity delayed flower initiation (experiments 13, 14), flower development (experiments 10, 13, 14, 17). It also reduced the number of flowers in the main inflorescence (experiments 13, 14, 17) and the precentage of open flowers (experiment 17). High light intensity increased the number of lateral stems (experiment 13). Stem length was usually slightly promoted by low light intensity (experiment 14, 17). Corm dry weight was proportional to light quantity (experiment 13, 14, 16, 17). The number of cormlets was reduced by low light intensity (experiment 10).Comparison of effects on light and temperature:17. Within the given ranges of these two factors the effect of temperature was usually greater than that of light. Only the number of lateral stems was determined primarily by the light conditions. As a rule, a higher temperature had a similar effect as a longer photoperiod (experiments 19, 20).Effect of planting date (experiment 21):18. The greatest number of leaves (and also the longest time to flower initiation) was found after planting in May and June, the smallest number of leaves after planting in February. The minimum number of days to flower initiation occurred after planting between November and January.19. The minimum number of days between planting and flowering occurred after planting in January and February; plants started in May took the longest time to flower.20. The number of flowers on the main inflorescence reached a maximum after planting in May and June and a minimum after planting between October and February.21. The number of lateral stems was high in plants started in June and low after planting in November and April.22. Stem length and plant height were greatest after planting between June and August and smallest after planting in February and March.23. Corm and cormlet dry weight were highest after planting in summer and low after planting in winter; the number of days between planting and harvest showed the opposite trend.Effect of planting density (experiment 21):24. In comparison to plants at a small distance, those at a wider distance were shorter, had more lateral stems and more flowers, a greater corm dry weight and more cormlets.25. The number of days to flowering was not affected by the planting density when the plants were started between November and March. Plants started between March and August flowered earlier when at a smaller distance; those started between September and November, however, flowered slightly earlier when at a greater distance.

The method of E.V. Borutski was used for determining the production of chironomids, that is, the dynamics of the number and biomass of the larvae were analysed, their death, a calculation of emergence and the number of deposited egg layings was carried out. In addition to the method of Borutski, the authors also calculated the seasonal dynamics of the number of larvae of the younger age stages in the microbenthos. | Translated from Russian into English