Punia, M.S.Seema Devi2016-12-032016-12-032005http://krishikosh.egranth.ac.in/handle/1/88949The present investigation was planned to study the callus induction and plant regeneration in soybean genotypes to screen the genotypes under in vitro and in vivo conditions and to find out the association between in vitro and in vivo screening for temperature tolerance using ten soybean genotypes (PK 416, PK 472, DS 9804, SL 518, PK 1042, JS335, DS 9814, AMS 97-1 and AMS97-2). Callusogenesis and plant organogenesis varied depending upon genotype, explant and medium used. Genotype DS 9804 was found most suitable for callus formation out of the two genotypes tested for callus formation and the MSS4 medium (MS0 salts + B5 vitamins + 5.0 mg/l 2,4-D + 0.5 mg/l IAA + 0.5 mg/l kinetin) was found better for callus induction. PK 416 genotype was found to be better having highest plant regeneration and average number of shoots / explant. MSR2 (MS0 salts + B5 vitamins + 2.0 mg/l BAP + 5.0 mg/l kinetin + 0.5 mg/l IAA) medium was found to be better for organogenesis. Calli of all the ten genotypes were cultured on MSS4 medium and were subjected to temperature stresses at 250C, 350C, 400C, 450C and 500C. 250C was taken as control 350C, 400C, 450C, 500C treatment were given for 4 hrs each in ovens. Genotypes PK 416, JS 335, PK 472, DS 9804 and SL 518 appeared to be temperature tolerant based on callus growth and stress index values. In the experiment, seeds of all the ten genotypes were cultured under in vitro (on solid and moist filter paper medium) and in vivo (plastic glasses and pots in screen house) at different temperature levels. The seeds were sown in the pots in screen house in the month of July 2004 having the temperature ranging from 390C - 410C. Temperature higher than 400C reduced seed germination, seedling length, relative water content and seed yield in all the genotypes. The temperature effects were very clear at 500C. The genotypes viz. PK 416, PK 1042, SL 518 and PK 472 were observed to be tolerant to heat stress. Bragg and AMS 972 were temperature sensitive genotypes and no seedling formation was observed at 500C in any of the genotypes. Protein and isozyme markers analysis also showed that some new bands appear in temperature tolerant genotypes and some disappear in susceptible genotypes. Callus growth, seed germination, seedling length and other parameters studied in genotypes were found to be better criteria for screening heat tolerant genotypes. All the techniques studied were found effective and reliable for screening soybean genotypes for high temperature tolerance.enThesis