[Effect of three population density on the growth and yield of three pea cultivars (Pisum sativum L.) [Spring, Perfected Freezer, Novella]]

The effect of spacing between rows on growth and yield of three green pea cultivars for fresh-consumption and with different growth patterns was evaluated to determine the best plant density and the most adequate row spacing. The trial was carried out at Buin in 1992 season. The cultivars used were Spring (early and with conventional foliage), Perfected Freezer (semi-late with conventional foliage) and Novella (semi-late and Afila). The evaluated row spacings were 30, 45 and 60 cm. The caloric units needed from seeding to harvest time in the green stage for Spring, Novella and Perfected Freezer cultivar, were 695.3, 886.4 and 890.7, respectively. The number of reproductive nodes, plant size, leaf area and dry matter of plants were affected when spacing between rows was reduced; the response was highly dependent on earliness and on the king of foliage of the cultivars. Thus, the most affected one was always Perfected Freezer, followed by Novella and finally by Spring; the latter cultivar showed the least variation which, in general, was not significant. The highest values for the leaf area index (LAI) were at the beginning of pod fill. For Spring, in the three row spacings (60, 45 and 30 cm) LAI values were 1.3, 1.2 and 2.2, respectively, Novella showed intermediate values between Spring and Perfected Freezer, ranging from 1.5 to 2.7. Finally, Perfected Freezer had the highest LAI values for row spaces, being 3.3, 4.3 and 5.3 for the same spacings as above. The yields per hectare, both in pod and green pea, increased significantly when narrowing the row spaces from 60 to 30 cm. Plant yield in the three cultivars decreased 20% on the average while yield per hectare increased about 50 to 66%. As relates to yield components, the number of pods per plant was only one affected by narrowing the spaces between rows. The number and weight of peas per pod showed no variations when the spacing between rows was reduced