~ 2711 ~ Journal of Pharmacognosy and Phytochemistry 2021; 10(1): 2711-2714 E-ISSN: 2278-4136 P-ISSN: 2349-8234 www.phytojournal.com JPP 2021; 10(1): 2711-2714 Received: 19-10-2021 Accepted: 21-12-2021 SV Yamgar Ph.D. Scholar, Department of Agricultural Botany, Mahatma Phule Agricultural University, Rahuri, Maharashtra, India SV Pawar Assistant Professor, Department of Agricultural Botany, Mahatma Phule Agricultural University, Rahuri, Maharashtra, India VP Chimote Associate Professor, Department of Agricultural Botany, Mahatma Phule Agricultural University, Rahuri, Maharashtra, India MP Deshmukh Associate Professor, Department of Agricultural Botany, Mahatma Phule Agricultural University, Rahuri, Maharashtra, India GC Shinde Associate Professor, Department of Agricultural Botany, Mahatma Phule Agricultural University, Rahuri, Maharashtra, India CA Nimbalkar Associate Professor, Department of Agricultural Botany, Mahatma Phule Agricultural University, Rahuri, Maharashtra, India Corresponding Author: SV Yamgar Ph.D. Scholar, Department of Agricultural Botany, Mahatma Phule Agricultural University, Rahuri, Maharashtra, India Expression of heterosis, residual heterosis and specific combining ability in yield and yield contributing characters of soybean ( Glycine max (L.) Merrill) SV Yamgar, SV Pawar, VP Chimote, MP Deshmukh, GC Shinde and CA Nimbalkar Abstract Development of hybrids in Soybean is difficult because of its small delicate flower structure and there is no that much differences in degree dominance in soybean in F1, F2 and later generations due to very low frequency of out crossing, small genetic load. An attempt has been made to estimate the magnitude and direction of heterosis, residual heterosis and their specific combing ability for eight yield and yield contributing characters in F1, F2 and F3 generations of four crosses in soybean. The experimental material consists of four rust resistant donor parents (JS 335 x SDP 10, JS 335 x SDP 18, JS 335 x SDP 30 and JS 335 x SDP 36 crossed with common female JS335 in line x tester manner. Resulting F1, F2 and F3 generations of four crosses) along with parents were studied to evaluate mid parent (MPH), Better parent (BPH) heterosis and specific combing ability (SCA). The material was sown in randomized block design in three replications at Agriculture research station, Kasbe Digraj, Sangli, MPKV, Rahuri in summer 2019. The observations were recorded on eight quantitative characters. The analysis of data showed highly significant differences for all the traits under study. The obtained results showed that F1 of JS335 x SDP 30 exhibited highest mid and better parent heterosis for days to flowering (-14.36%),days to maturity (-6.83%), primary branches per plant (32.20%), number of pods per plant (31.42,64.85%) and 100 seed weight (34.83, 20.92%). The cross JS335 x SDP18 expressed highest heterosis for plant height (25.08,21.21%), Cross JS335 x SDP10 exihibited for number of pods per cluster(18.37,16.0%) and yield per plant in JS335 x SDP36 (32.90, 41.57%). However, among the F2 generations of four crosses, highest residual heterosis over mid and better- parent was recorded in JS335 x SDP18 for plant height (21.17,17.42%), number of primary branches per plant(16.40 % MPH),100 seed weight (21.81%) and yield per plant (37.09, 53.87%).The F2 of JS335 x SDP10 exhibited residual heterosis for number of pod per cluster(14.03%MPH).The F2 of JS335 x SDP 30 exhibited highest residual heterosis for number of pods per plant (22.72 and 53.93%) and 100 seed weight(20.61%MPH). In F3 generations, high amount residual heterobeltosis was recorded in JS335 x SDP18 for plant height (19.22, 15.53%), Pod per plant (24.40% BPH), 100 seed weight (21.81%MPH) and yield per plant in JS335 x SDP30 (37.40%BPH). Keywords: heterosis, line x tester, residual heterosis, specific combining ability, soybean Introduction Soybean, Glycine max (L.) Merrill, is a member of the family Leguminasae and sub- family Papilionaceae with chromosome number 2n = 40. It has become a miracle crop well known as ‘Golden bean’.Soybean seed contains approximately 37-41 per cent protein, 18-21 per cent oil, 30-40 per cent carbohydrate, and 4-5 per cent ash (Hulse, 1996) [10] . However, Soybean is highly self-pollinated crossed so it is difficult to exploit heterosis in soybean due to unavailability of male sterility system, less number of pollen vector, delicate flower structure, there is no that much differences in degree dominance in soybean in F 1 , F 2 and later generations due to very low frequency of out crossing, small genetic load, highly inbred. Heterosis is estimated for amount number of genes and with dominance effect it is easier to obtain a hybrid than a line with superior genotypes. The most accepted hypotheses to explain heterosis involve dominance and the over dominance, besides epistatic effects. The superior performance of F 1 generations over better-parent is more helpful for determining the feasibility of heterosis whether it commercial exploitable or not. However it also showed potent parental combinations for producing the highest level of transgressive segregants. Transgressive segregation is result of heterotic effect of residual dominant genes from F 2 , F 3 to onward generations. Line x tester analysis which provide information of GCA, SCA and variance their effect, In this study specific combing ability estimated which provides information of best cross combination for particular character and predominant dominant gene