Cold tolerance during early reproductive growth of chickpea (Cicer arietinum L.): characterization of stress and genetic variation in pod set

Abstract

Most chickpea cultivars grown in regions where temperatures fall below 10°C continue to flower but fail to set pods. Research was conducted in Hisar, a subtropical location in northern India, to characterize cold stress and examine genetic variation in pod and seed set at low temperatures. Lines of various maturity groups were used so that phenological timing of stress differed with line. Flowering was therefore synchronized with a cold spell to evaluate tolerance. A substantial variation was found both in field and controlled environments. Two early maturing advanced breeding lines, ICCVs (ICCV = ICRISAT Chickpea Variety) 88502 and 88503, showed good pod set in cold spells, but seed growth in them was limited. Evaluation of the parents indicated possible contribution of a germplasm from the former Soviet Union, K 1189 (ICRISAT chickpea germplasm collection No ICC 8923), to cold tolerance. Experiments in controlled environments indicated that pod set can occur at night temperatures of 0-5°C if daytime temperatures exceed 20°C. Seed development required a higher threshold temperature than pod set. Thermal regimes of 15/5 and 15/0°C day/night were useful in preliminary screening of germplasm lines for cold tolerance