Exploitation of Heterosis for Seed Yield and its Contributing Traits in CMS Based Hybrids of Indian Mustard [Brassica juncea (L.) Czern and Coss]

In the present study, line× tester analysis was carried out at Castor-Mustard Research Station, S. D. Agricultural University, Sardarkrushinagar, Gujarat, India during rabi 2018–19 (October 2018 to February 2019) in order to estimate all three types of heterosis (relative heterosis, heterobeltiosis and economic heterosis) for identification of superior cross combinations of Indian mustard [Brassica juncea (L.) Czern&Coss]. Thirty-five hybrids along with five CMS lines, seven testers and check GDM 4 were evaluated for ten different traits. The F1 generation of all the crosses exhibited fertility restoration with pollen fertility except F1 crosses with Vardan, Rohini and SKM 319 fertile line (0%). The remaining crosses exhibited pollen fertility ranging from 68.26% (Kranti×SKM 303) to 85.17% (Kranti×Mori ‘R’ 1-18). The analysis of variance for parents, hybrids and parents vs. hybrids revealed that mean sum of squares of parents were highly significant for majority of the characters except days to maturity. Whereas, hybrids differed highly significant for all the characters. Comparison of mean squares due to parents vs. hybrids was found significant for almost all the characters except number of seeds siliqua-1 and oil content. This indicates that considerable amount of genetic variability present among the parents and hybrids for all the characters studied. On the basis of per se performance, three hybrids viz., Kranti×Mori ‘R’ 1-18, SKM 9928×PusaAgrani and SKM 9928×Mori ‘R’ 1-18 were foundpromising for seed yield plant-1 over the standard check GDM 4.With respect to heterosis, one of the hybrid Kranti×Mori ‘R’ 1-18 (17.85 %)manifested significant and positive standard heterosis for seed yield plant-1.

Combining Ability and Heterosis Studies in Blackgram [Vigna mungo (L.) Hepper]

Background: Blackgram is one of the important pulse crops. To improve the yield levels in this crop, studies on combining ability and heterosis are a method to select suitable parents based on their general and specific combing ability and heterotic effects for use in further breeding programmes. Methods: The present investigation was conducted during Kharif 2019. The crosses were made in line × tester mating fashion during the summer season of 2019 for obtaining 15 (Fifteen) crosses. Fifteen hybrids and their parents (3 lines and 5 testers), including one check, were grown and eleven traits were recorded to estimate general and specific combining ability in the modified line × tester method. Result: In the present investigation the predominance of non-additive gene effect in the expression of plant height, no. of clusters per plant, no. of pods per cluster, no. of pods per plant, seed yield per plant, biological yield per plant, 100 seed weight and harvest index was found. Among parents, KUP 18-346 and KUP 18-350, Pant U-31 were found to be good general combiner for seed yield and some other characters. Hybrids viz., KUP 18-350 × Pant U-31, KUP 18-345 × T-9 and KUP 18-345 × Uttara were found promising combinations for seed yield per plant. Hybrid, KUP 18-350 × Pant U-31 recorded significant standard heterosis, heterobeltiosis and average heterosis for most of the important characters.

Study on Heterosis for Yield and Yield Contributing Traits in Desi Cotton (Gossypium arboreum L.)

The present investigation entitled “Studies on Heterosis for Yield and Yield Contributing Traits in Desi Cotton (Gossypium arboreum L.) was undertaken with the objective to study the scale of heterosis over mid parent (Average heterosis), better parent (Heterobeltiosis) and standard check (Standard heterosis). The line x tester method of analysis was followed involving four females viz., PA 811, PA 839, PA 808 and PAIG 380 and six males viz. AKA 8, JLA 505, PA 812, AKA 7, PA 08 and Phule Dhanwantry for study of heterosis for various yield and yield contributing characters. The F1’s and theis parents were evaluated in Randomized Block Design with two replications. Observations were recorded on Days to 50 % flowering, Plant height (cm), Number of sympodia, Number of bolls/plant, Boll weight (g), Seed index, Seed cotton yield/plant (g) and Lint index. The magnitude of heterosis was highest for seed cotton yield per plant, which was recorded to the extent of 115.28 % over standard check PKV Suvarna in the cross PAIG 380 x AKA 8 followed by 109.68 % over standard check PKVDH 1.

Estimation of Heterosis Among Potato (Solanum tuberosum L.) Crosses in Ethiopia

Determination of heterosis in tetraploid potato crosses is necessary for identification of superior genotypes for variety development or breeding program. However, producing heterotic potato genotypes through local crossing is not a common practice in Ethiopia. Hence, this study was conducted to estimate the magnitude of better, and standard check heteroses in potato clones that are produced from local crossing. This will help identify potential of hybrid for future breeding schemes. Heterosis of 75 clones were evaluated using a 9 x 9 Simple Lattice design. Results of the analysis of variance showed significant differences for all the growth characters, except medium-sized tubers and specific gravity of tuber. These results indicate the presence of genetic variability among the samples. The clones exhibited as high as 55.62 and 58.31 t.ha-1 marketable and total tuber yield, respectively. These clones also displayed mid, better parent and standard heterosis of 118.8%, 90.5% and 239.1%, respectively, for marketable tuber yield. This result indicates the presence of high magnitude heterosis which could be used to exploit the hybrid vigor. In addition, mid, better parent, and standard check heterosis were estimated at 79.36%, 61.04% and 209.17% for total tuber yield, respectively. Our results show the highest chance of getting heterotic offspring than parental and standard check varieties to developing new potato varieties. The information generated from this study would be valuable for researchers who intend to develop high-yielding varieties of potato

Evaluation of Maize (Zea mays L.) Hybrids for Economic Heterosis under Different Soil Moisture Regimes at North Eastern Plain Zone of India

The present experiment was conducted to understand the effect of soil moisture status on the economic or standard heterosis in fifty maize hybrids for grain yield and flowering traits. The trials were planted at Agricultural Research Farm, Banaras Hindu University, Varanasi in alpha-lattice design with two replications. The analysis of variance revealed the significant differences for grain yield and flowering related traits such as days to 50% anthesis, days to 50% silking and anthesis-silking interval under all the moisture conditions including optimal, managed drought and managed waterlogging conditions. Significant amount of heterosis was observed over the selected check P3502 for all the traits under study; however, the magnitude and direction varied with traits and with soil moisture level. For days to 50% anthesis, hybrids ZH17192, VH112926, VH123021, ZH114250, ZH16929 and ZH16930 were showed significant negative heterosis under all the moisture conditions that explained earliness under both moisture-stress and normal conditions. Among the tested hybrids, VH123021 and ZH16929 were recorded significant negative standard heterosis for flowering traits; and significant positive heterosis for grain yield under all the three moisture conditions. Six hybrids under drought, seven hybrids under optimal and two hybrids under waterlogged condition showed positive standard heterosis for grain yield. Further evaluation of these hybrids at multi-locations and multi-year is advisable to confirm the promising findings observed in our study. This study could be valuable for development of climate-resilient maize hybrids.

Study on Standard Heterosis for Yield, Quality and its Attributing Characters in Rice (Oryza sativa L.) Hybrids under Aerobic Cultivation

Field experiments were conducted for development and evaluation of aerobic rice hybrids during2015-16 to 2016-17 years. In the first experiment sufficient amount of variability was observed for grain yield per plant and its components among 125 genotypes evaluated in aerobic condition. Among these eight genotypes were the top ranking yield in aerobic conditions and good restorers tested by Test Cross Nursery and Rf3, Rf4 fertility restorer gene screening. Than 32 hybrids were produced involving 4 CMS lines (CMS23A, CMS59A, CMS64A and IR68897A) and 8 testers (SVHR-3005, NH-12-103R, KMP-128, MTU-1001, KMP-175, SV-315-081R, RNR-21280 and MTU-1075) and evaluated along with three checks (viz., hybrid check, KRH-2, inbred checks, MTU-1010, MAS-946) under aerobic situation and carryout standard heterosis analysis, to identify best heterotic hybrids over local checks. CMS23A x SV-315-081R manifested high heterotic effects (>20%) for grain yield per plant over the standard checks, besides for important components. Few more CMS59A x KMP-175, CMS59A x RNR-21280, CMS23A x MTU-1001, IR-68897A x MTU-1075 and CMS23A x MTU-1075 were also identified as potential hybrids in view of higher amount of heterosis. For quality, CMS64A x RNR-21280 (hulling percentage, milling percentage, head rice recovery and kernel elongation ratio) and CMS23A x SV-315-081R (head rice recovery, kernel length, L/B ratio and Kernel length after cooking) were best heterotic hybrids. Two crosses viz., CMS59A x SVHR-3005 and CMS64A x SVHR-3005 expressed negative heterosis for kernel breadth and positive heterosis for kernel L/B ratio which was desirable.