Assimilation and partitioning of dry matter and nitrogen in Hyprosola, a more determinate mutant of chickpea, and in its parental cultivar

Abstract

Nodulated plants of Hyprosola, a gamma-ray induced mutant of chickpea ( Cicer arietinum L.) and of its parental cultivar, Faridpur-1, were grown to maturity in a temperature controlled glasshouse in a rooting medium of sand–vermiculite watered with nutrient solutions with or without combined nitrogen. Leaf and stem numbers of the plants not given supplemental nitrogen were determined at 10–11 day intervals, and the dry weight and nitrogen content of nodules of the plant parts were measured successively from 29 days after sowing to maturity on day 121. The major difference between the growth patterns of the two cultivars was the significantly greater vegetative growth of the parent, Faridpur-1, during the last 3 weeks of pod-filling, compared with the mutant, Hyprosola. The higher harvest index of the mutant led to a similar yield of seed per plant by both cultivars in the N-free medium, but the mutant was higher-yielding with supplemental N, despite the low plant density of one plant per 25 cm pot for both cultivars. The mutant also had the higher N harvest index. The role of the more determinate growth pattern of the mutant in determining its higher seed yield and higher seed protein content than Faridpur-1 under field conditions in Bangladesh and neighbouring countries is discussed.