Dry matter accumulation and nitrogen partitioning between shoot and root of pea (Pisum sativum L.) cultivars

Dry matter and nitrogen (N) accumulation of three field pea cultivars having different morphological characters were compared under different levels of nitrogen in a field trial conducted in 1996/1997. The cultivars used were Allure (semi-leafless, semi-erect), Beacon (conventional, determinate) and Whero (conventional, indeterminate and scrambling). The N rates were 0, 30 and 60 kg/ha applied at 26 days after sowing (DAS). Shoot growth was measured at fortnightly intervals beginning from the initiation of the N treatments, while roots were sampled at 26, 40, 54 and 82 DAS. Cultivar differences in shoot growth were usually significant while N application had no influence on shoot dry matter accumulation. Throughout most of the growing season, Allure produced the highest shoot dry weight. Application of N did not affect root dry matter content at any stage for all cultivars. Beacon produced the lowest root weight at 26 and 40 DAS. However, at later stages (54 and 82 DAS) there were no significant differences among the cultivars. Allure had higher shoot to root ratios than the other cultivars. Nitrogen had no significant effect on either shoot or root N accumulation. However, cultivar differences were observed in N concentration and total N content of shoots. Allure had a lower N concentration than the other cultivars throughout most of the experimental period. Initially Beacon contained a significantly lower N content in the shoot compared with the other two cultivars. However shoot N gain in Beacon increased gradually and approached that of Allure at later growth stages. The N partitioning between shoot and root of peas was not affected by either cultivar or N application during the growing period.