Ontogenetic Characteristics of Field Pea in a Semiarid Environment

Identifying key yield components can help establish better crop management strategies to increase crop yield. The present research was conducted in south-western Saskatchewan in 1999 and 2000 to determine the interrelationships among various yield components and their direct and indirect effects of each component on seed yield of field pea (Pisum sativum L.). The semi-leafless cultivar Carrera was planted at the populations of 35, 50, 65 and 80 plants m 2 on conventional summerfallow (CS) and no-till wheat stubble (NT). The coefficients (b values) from path analyses revealed that the seed yield of field pea depended primarily upon total number of pods per unit area (b = 1.41 for the pea on CS and 1.39 on NT) and secondarily upon seeds per pod (b = 0.59 for the pea on CS and 0.44 on NT). The association between weight per seed and yield was either weak (b = 0.14 for the pea on CS) or negligible (b = 0.07 for the pea on NT). Among the various yield-related variables, total number of pods per unit area was the greatest yield contributor that largely relied on plants m 2 (b = 1.35 for the pea on CS and 0.97 on NT) and on pods plant 1 (b = 0.78 for the pea on CS and 0.74 on NT). Plants m 2 had a negative, indirect effect through pods plant 1, as did pods plant 1 through plants m 2, but those indirect effects were counterbalanced by the direct effects of the components on total pod production. Weight per seed was highly and positively related to the length of reproductive growth. Seed yield in a dry environment can be increased by increasing pod production, whereas weight per seed can be improved by prolonging reproductive growth to increase the cotyledon cell size.