Soybean - Bragg
Crops Season : Kharif Season
Name of Variety : Bragg
Yield : 15-20 (क्विं. प्रति हे.)
Duration : 112-115 दिनों में
Water requirement : Water is not required in kharif season, but it is necessary to require 1 or 2 irrigation as per requirement.
Area of Cultivation (State) : Throughout India
Specialty : Resistant to bacterial pustules, susceptible to YMV.
Shape and type : White flowers, grey pubescence, yellow seed coat, black hilum, brown pods, determinate.
Description : Variety 'Bragg' (Jackson x D49-2491) of soybean (Glycine max. (L.) Merrill) was found to be high yielding and widely adaptable throughout India. Its yield stability, however, is unsatisfactory, probably due to low germinability necessitating use of higher seed rate. With the main objective to rectify this defect, mutagenesis involving chemical as well as physical mutagens was used. Dry seeds were treated with EMS or MMS (0.2, 0.4 and 0.6%), or gamma rays (15, 20 and 25 kR) with and without additional exposure to UV (2 hrs at 260 nm) in 1982. In M2, a mutation frequency ranging from 2.24 to 22.85% was observed. Screening of M2 and of subsequent generations yielded a broad spectrum of mutations. Some of the mutants are agronomically useful. Among them, mutant 'T214' resulting from 25 kR gamma rays + UV, was found to possess better germinability (+15%), earliness (5 days) and high yield during both rainy and post-rainy seasons in 1986 and 1987, when compared with the parent variety 'Bragg'. The mutant has smaller seed-size (TGW 125 g) than the parent (145 g). In soybean, large-seeded varieties were reported to have poorer seed germinability. Thus, the better germinability of the mutant might be related to its reduced seed size. Seeds of the mutant show a light brown colour of the hilum in contrast to the black hilum of 'Bragg'. In other characters the mutant is similar to 'Bragg'. The mutant should have potential for commercial cultivation in India. For confirmation of its agronomically superior performance, it is undergoing national evaluation in multilocational trials under 'All India Co-ordinated Research Project on Soybean (ICAR)'. The strain has been named 'NRC-2'. (author)