Coefficients of correlation for a number of different characters were determined between the mean performance of the single crosses of inbred lines of corn and the performance of these lines in crosses with a commercial variety or with a varietal mixture. Coefficients of correlation also were determined between the mean performance of the crosses of several inbred lines used in two series of crosses. From a comparison of these correlations it is concluded that crosses with open-pollinated varieties may be used efficiently in the preliminary testing of new lines.

This study was made as a preliminary investigation to determine whether certain procedures might be of use in making studies of soil structure. The Bouyoucos method of measuring soil permeability to water seems satisfactory as a percolation method. The method is sufficiently sensitive to distinguish soil types that show marked differences in behavior in the field, and to distinguish between surface and subsoils when these are appreciably different. The method also distinguishes the effects of treatments and different rates of treatment rather consistently. The results likewise correspond with the field behavior of the soils. The plasticity indices appear to indicate significant structural differences. The more desirable soil structures are associated with a low plastic range and the refractory soils with a high plastic range. There is little or no correlation between soil structure and the amount of colloidal material. Chemical treatments may prove helpful to improve soil structure in the field, but the feasibility of such improvement can be determined only by field trial.

With few exceptions, red clover is self-incompatible. Reciprocal crosses between 30 pairs of unrelated parents sampled in a population, were all compatible. Three full-sib F2's from one of these crosses showed, in 8 x 8 diallel crosses, 2, 2 and 4 incompatibility groups, and an F5 showed, in a 15 x 15 diallel cross, 2 incompatibility groups. The data were explained by a (large) series of S alleles, as proposed by East for Nicotiana and by Filzer for Veronica.In a number of progenies, male-sterility (degenerate anthers) was found and a recessive factor was identified.Seed-coat colour (yellow versus violet) was polymerically controlled (up to 5 cumulative factors), complicated by environmental and within-plant variation. In certain progenies a factor for violet (v) and an intensifier (X) could be identified. The quality of yellow and of violet was controlled by C-c and by R-r, respectively.Flower colour was determined by the factor G for anthocyanin production and by B-b for purple or pink, along with at least 3 intensifiers of purple.Two chlorophyll abnormalities depended on recessive factors (chlorina and albina) and one was plasmatically inherited (albomaculata). Two types of dwarfs (nanella and nana) were single recessives.

With few exceptions, red clover is self-incompatible. Reciprocal crosses between 30 pairs of unrelated parents sampled in a population, were all compatible. Three full-sib F2's from one of these crosses showed, in 8 x 8 diallel crosses, 2, 2 and 4 incompatibility groups, and an F5 showed, in a 15 x 15 diallel cross, 2 incompatibility groups. The data were explained by a (large) series of S alleles, as proposed by East for Nicotiana and by Filzer for Veronica.In a number of progenies, male-sterility (degenerate anthers) was found and a recessive factor was identified.Seed-coat colour (yellow versus violet) was polymerically controlled (up to 5 cumulative factors), complicated by environmental and within-plant variation. In certain progenies a factor for violet (v) and an intensifier (X) could be identified. The quality of yellow and of violet was controlled by C-c and by R-r, respectively.Flower colour was determined by the factor G for anthocyanin production and by B-b for purple or pink, along with at least 3 intensifiers of purple.Two chlorophyll abnormalities depended on recessive factors (chlorina and albina) and one was plasmatically inherited (albomaculata). Two types of dwarfs (nanella and nana) were single recessives.

There are several advantages of a satisfactory mechanical straw-breaking test for determining straw strength of oats. Its chief advantage is that it can be used where lodging of the grain does not occur. Other advantages are that it can be used to supplement observations on field lodging and to test hybrids where the quantity of material is limited. Data obtained from the straw-breaking tests at Aberdeen on the registered improved varieties clearly separate the midseason from the early varieties. Under the almost ideal conditions for oats found under irrigation in southern Idaho, the midseason and larger-strawed varieties undoubtedly develop the stronger straw. Significant correlations were found to exist between the breaking strength of straw and several plant characters, such as weight of panicles, weight of grain, weight of straws broken, height of culm and width of second leaf. A correlation coefficient of +.863 +/- .030 was obtained breaking strength of straw of 32 registered improved varieties for the years 1929 and 1930. There was close agreement between the breaking strength of straw of standard varieties grown in the regular yield test nursery of 1929 and 1930. A correlation coefficient value of +.702 +/- .057 was obtained. The range in the breaking-strength readings for these varieties was not so great as that for the registered improved varieties. This is due primarily to the fact that the standard varieties are all of the midseason type with straw of similar height and diameter. In general, the reputed stiff-strawed varieties as determined by field observations when subjected to a mechanical straw strength test, showed the highest resistance to breaking.

Previous work having shown that the base exchange property of the mineral matter of soil colloids is probably due largely to one compound and that the chemical composition of this compound is A1(2)O(3.4) SiO(2).XH(2)O, it seemed reasonable to believe that, besides this compound, mineral soil colloids consist largely of free silica, free alumina, free titanium oxide, free iron oxide, and possibly kaolinite. From a total analysis of soil colloids, an alkali-soluble alumina and silica determination, and a base exchange capacity determination, it should he possible, by calculation, to formulate a fairly accurate picture of the mineralogical composition of soil colloids. It was the purpose of the present study to investigate this possibility. In order to make the calculation possible, it was necessary to determine accurately the base exchange capacity of the base exchange compound. For this purpose samples of the purified base exchange compound were prepared from three different bentonites and the exchange capacities of these samples were determined by both the exchange method and the titration method. One of the samples gave exactly the same exchange capacity value by the two methods, and it was assumed that this sample was probably the purest. The exchange value of this sample was used, therefore in calculations of the mineralogical composition of the soil colloid. A sample of soil colloid was prepared from Colby silt loam subsoil and this was subjected to a base exchange capacity determination and also to the other analyses referred to. From the base exchange capacity determination, it appears that this soil colloid consists of a little more than 50% of the base exchange compound. The amounts of free silica and alumina are rather small. There exists an excess of combined silica and alumina over that required for the base exchange compound. This excess of these two oxides was not in the ratio found in kaolinite, and since other evidence did not indicate the presence of kaolinite, it was assumed that this combined silica and alumina were probably present in the form of chlorites. Chlorites are found in abundance in the weathered portion of soils, and their presence in the colloid would also account for the appreciable amount of magnesia found. A portion of the iron oxide was probably also present in the chlorites. On the basis of this assumption, 30 to 40% of the soil colloid consisted of chlorites.

Cytological irregularities were found to be occurring in all three of the varieties studied and no plants failed to show at least a small percentage of cytological aberrations during maturation of their pollen mother cells. As measured by cytological aberrations, Marquillo was found to be more unstable than either Marquis or Minn. No. 2303, whereas Marquis and Minn. No. 2303 were about equal in this respect, although Minn. No. 2303 gave a lower percentage of non-conjunction. Since Minn. No. 2303 is the result of an attempt to combine the desirable characters of the durum and vulgare groups of wheat and therefore shows, as far as practical purposes are concerned, that a germinally stable variety can be obtained from crosses involving these two species, it is of special interest to the agronomist and plant breeder. The correlations found to exist between the different aberrations strongly indicate that the occurrence of micronuclei may be taken as a criterion of the frequency of occurrence of non-orientation and non-conjunction. If such proved to be the case, the work and time involved in determining the germinal instability of a variety or cross may be greatly reduced, and, consequently, the number of plants that can be studied materially increased. It is comparatively easy to find the tetrad stage of microsporogenesis at which time the percentage of cells showing micronuclei are determined, but it is rather difficult to find the proper stage for determining the percentage of pollen mother cells that exhibit non-orientation and non-conjunction. The cytological aberrations in the parent plants of Marquillo were found to be positively associated with variability of some characters of the progeny. These aberrations were also found to be negatively associated with the means of the progeny of the Marquillo plants studied cytologically. The latter relationship was found to be more marked for Marquis than for Marquillo. No significant association could be demonstrated between either the different cytological aberrations in Minn. No. 2303 or the cytological aberrations and the variability or means of the characters of the progeny. These results with Minn. No. 2303 may be accounted for by assuming that it is essentially a homogeneous population so far as cytological aberrations are concerned. This assumption is not without some foundation as Minn. No. 2303 is not as far removed from an individual plant selection as either Marquillo or Marquis. The results with Marquillo and Marquis are explainable if these two varieties are composed of a heterogeneous population as far as cytological aberrations are concerned. In this case, selection within either Marquillo or Marquis would be expected to produce a strain with a lower percentage of cytological aberrations than the parents.

This investigation was undertaken for the purpose of determining the nature and availability of both the native and applied phosphates in the soils of six Kentucky soil experimental fields. The influence of lime on the availability of the phosphates was also studied. The distribution or localization of the native and applied phosphates in the fractions of soil separates was determined for a representative soil for the purpose of ascertaining in what fraction or fractions of the soil separates the fixation of the applied phosphate occurs. For the relatively available phosphorus, carbonated water and N/500 sulfuric acid buffered to a pH of 3.0 were used as solvents. Very small amounts of relatively available phosphorus were extracted from the soils of the check plats. These amounts were roughly proportional to the total phosphorus which indicates that the native phosphates are essentially of one kind in these soils. Prolonged extraction of the soils gave a solubility of the native phosphates approximately equivalent to that of dufrenite. The use of lime did not seem to influence the availability of the native phosphates. The availability of superphosphate varies with the capacity of soils to fix phosphates in relatively insoluble and unavailable forms. On this basis, the soils studied may be divided into two groups. The first group of low capacity in this respect includes the DeKalb silt loam at Berea, the Decatur silt loam at Russellville, and the Memphis silt loam at Mayfield. The second group of high capacity in this respect includes the Tilsit silt loam at Greenville, the silt loam at Campbellsville derived from Waverly shale, and the silt loam at Fariston derived from Eastern Coal Basin shale. The use of lime reduces the rate of fixation into relatively insoluble phosphates in all of the soils, but equal applications of lime are much more effective in this respect on soils of the first group than of the second group. The use of lime reduces the rate of solution of rock phosphate in all of the soils. This reduction is greater in soils of the first group of low capacity to fix phosphorus in relatively insoluble forms than in soils of the second group of high capacity in this respect. Lime exercises a positive influence on crop response to rock phosphate on soils of the first group and a negative or neutral influence on soils of the second group. In the soils of the second group, where a high capacity exists for fixing phosphates in relatively insoluble forms, the rate of solution of rock phosphate is also high, but a deficiency in readily available phosphorus exists, due to its rapid fixation as relatively insoluble and unavailable phosphates. The use of lime reduces the availability of the manganese in all of the soils studied. No correlation exists, however, between the reduction in available manganese and the positive or negative influence of lime on crop response to rock phosphate. The great reduction in the availability of manganese in the case of the Fariston soil, where 6 tons of lime were applied, suggests that manganese deficiency may be responsible in part for the negative influence of lime on the phosphates where very large applications of lime have been made. Fixation of phosphates in soils occurs largely in the fine clay fraction, but appreciable amounts are also fixed in the coarse clay and silt fractions.