Effect of Photoperiod in Advanced Breeding Lines of Soybean [Glycine Max (L.) Merrill]

The present investigation was conducted during rabi and kharif season of 2008–09 at the Crop Research Centre, G.B. Pant University of Agriculture and Technology, Pantnagar, India. The objective of this investigation was assessment of the response of elite breeding line to different photoperiods, i.e. kharif and Rabi, because of Soybean is photosensitive crop as it responds to the critical day length of light. The experiment was carried out with 132 genotypes in Augmented Block Design (ABD) with five checks (JS 335, Shilajeet, PK 327, PS 1092 and PS 1225). In kharif season, three genotypes (ABL-28, ABL-30, and ABL-39) were found significantly superior for days to full flower, only two genotypes (ABL-49, ABL-50) for number of nodes per plant, 11 genotypes (ABL-6, ABL-10, ABL-4, ABL40, ABL-4, ABL-49, ABL-50, ABL-61, ABL-88, ABL-98 and ABL-122) for number of primary branches per plant and 15 genotypes (ABL-2, ABL-3, ABL-4, ABL-10, ABL-12, ABL-33, ABL-40, ABL-41, ABL-51, ABL-53, ABL-55, ABL-56, ABL-85 and ABL-103) for harvest index than their respective best checks Shilajeet, JS 335, PK 327 and PS1225, respectively. During kharif, seed yield per plant displayed highly significant and positive correlation with number of pods per plant, primary branches per plant, biological yield per plant, harvest index and yield per ha. (Kg.) whereas negative association with number of node per plant and in rabi seed yield per plant had highly significant positive correlation with number of pods per plant. Based on estimates of correlation between both seasons, significant correlation was observed between days to flower initiation (R1) in kharif season with days to seed initiation (R5) during rabi season, days to full flower (R2) during Kharif season with days to pod initiation (R3) and days to seed initiation (R5) in rabi, days to pod initiation (R3) in kharif with days to flower initiation (R1) and days to full flower (R2) in rabi, days to seed initiation (R5) in kharif with days to flower initiation (R1) in rabi and days to full seed (R6) in kharif season with days to flower initiation (R1) and days to full flower (R2) in rabi. Out of 137 genotypes which were studied during both the seasons, only 17 genotypes (including 13 breeding lines and 4 check varieties viz., ABL-1, ABL-3, ABL-12, ABL-13, ABL-19, ABL-23, ABL-28, ABL-39, ABL-40, ABL-41, ABL-53, ABL-87, and ABL-89 with four checks JS-335, Shilajeet, PK-327, PS-1092 got matured in both the season and considered to be photoinsensitive thus, can be further evaluated for stability parameter over the locations and years.