Biomass, Harvest Index and Yield in Relation to Changes in Photo-thermal Regimes in Soybean (Glycine max L. Merrill.) Genotypes

摘要

Fifteen photo- and thermo-insensitive early maturing genotypes and five promising main season normal maturing genotypes of soybean which were determinate in growth and photo-thermo sensitivity were evaluated for their agronomic performance under a wide range of photoperiod and temperature conditions manipulated through five sowing dates (February 23, March 20, April 14, May 9 and June 3). Genotypes, sowing dates and their interactions with environments were highly significant for the traits studied.The significant GE interactions for biomass production, harvest index (HI) and grain yield (GY) indicated that the tested genotypes ranked differently across diverse environments for these characters. In early maturing genotypes, longer day-length and higher temperature produced bold seeds and high HI but fewer yields. Main season genotypes produced higher biomass and GY than that of early maturing genotypes in all the sowings. Early maturing genotypes viz. E7 and El9 had higher GY whereas SL 295 and Pb. No. 1 recorded higher GY among main season genotypes over all the sowing dates. Biomass and HI were important determinants of GY as evident from their significant positive regression coefficients with GY. It is concluded that for main season genotypes(May and June sowing) GY can be increased by increasing HI and enhancement of biomass production in early maturing-photo and thermo insensitive in February-March sowing could lead in yield improvement. Study also demonstrated that early maturing photo-thermo insensitive genotypes of soybean could be grown successfully during spring/summer (February to June).