Harnessing heterosis in Brassica juncea (L.) Czern. & Coss.: Challenges in commercial hybrid production and future strategies

Heterosis Assessment for Stem Rot Resistant Hybrids in Indian Mustard (Brassica juncea L.)

Brassica juncea (L.) is a key oilseed crop that is extensively grown worldwide for edible oil and animal feed. However, various biotic and abiotic stresses, together with a narrow genetic base, keep productivity below the desired level, underscoring the need to expand the genetic base and utilise heterosis to develop superior cultivars with resistance or tolerance to major diseases. The present investigation was undertaken to evaluate standard heterosis for seed yield and its attributing traits among 50 diverse cross combinations developed during Rabi, 2025 and evaluated during Rabi, 2026, along with the zonal (Rohini) and national (Kranti) checks at the Research Farm, Zonal Agricultural Research Station, Morena, RVSKVV, Gwalior, M.P., India, using putative donors for stem rot resistance. Significant variability existed for yield and its attributing characters, with seed yield per plant ranging from 11.2 g for the cross L-6 × BC1F5 of Pusa Jai Kisan × Brassica napus 114 to 42.0 g for the cross Pusa Bold × F3 of Pusa Jai Kisan × Brassica napus 114. Strong hybrid vigour was evident in cross combinations such as Varuna × BC1F5 of Pusa Jai Kisan × Brassica napus 114, Sej-2 × BC2F1 of Pusa Jai Kisan × Brassica napus 114, and Shraddha × BC2F1 of Pusa Jai Kisan × Brassica napus 114, which showed high positive heterosis for yield and its component traits, including number of siliquae per plant, number of seeds per siliqua, 1000-seed weight, and earliness. The yield potential of these crosses was further supported by architectural traits, including longer racemes and a higher number of branches per plant. These results highlight the potential of targeted hybridisation to overcome current yield constraints. These promising cross combinations indicate that heterosis breeding may be used to improve yield in Indian mustard while incorporating resistance to Sclerotinia stem rot disease.

Combining Ability Analysis for Seed Yield and Associated Traits in Indian Mustard (Brassica juncea L. Czern & Coss.)

Indian mustard belongs to the family Brassicaceae and the genus Brassica and is a major oilseed crop cultivated in India. Worldwide, it is the third-ranked oilseed crop in terms of consumption after palm oil and soybean. However, productivity remains below its potential because of various biotic and abiotic stressors coupled with a narrow genetic base, highlighting the need to broaden the genetic base and exploit heterosis to develop superior cultivars. Therefore, in the present study, general and specific combining ability analyses were conducted to assess the combining abilities of the parents and the performance of hybrids at the Zonal Agricultural Research Station, Morena, Rajmata Vijayaraje Scindia Agricultural University, Gwalior, M. P., India, during Rabi 2026. During the present investigation, 16 yield-attributing traits were evaluated using 10 lines, 3 testers, and their thirty F1 hybrids developed through a line × tester mating design to estimate the magnitude and direction of combining abilities. Among the lines and testers, GCA effects showed that parents viz., Pusa Bold, Rohini, Varuna, and Vardhan were good general combiners because they exhibited desirable negative and highly significant GCA effects for days to 50% flowering, days to siliquae initiation, and plant height. However, Pusa Bold was recognized as a good general combiner because it displayed positive and highly significant GCA effects for the maximum number of quantitative traits, including seed yield per plant and harvest index. The cross-combination Pusa Jagannath × PAB-2014-4 had the highest SCA effect for seed yield per plant, biological yield, number of siliquae per plant and number of primary branches per plant, while Maya × PAB-2014-8 showed high SCA effects for seed yield per plant, biological yield and number of siliquae on the main raceme.

Estimation of Standard Heterosis in Indian Mustard [Brassica juncea (L.) Czern. & Coss.]

The present study evaluated standard heterosis for seed yield and 15 associated traits in 40 cross combinations of Indian mustard [Brassica juncea (L.) Czern. & Coss.]. Crosses developed during Rabi 2025 were evaluated during Rabi 2026 at the Experimental Farm, Zonal Agricultural Research Station, Morena, Madhya Pradesh, India, in a randomized block design with three replications. The zonal check Maya and national check Kranti were used for comparison. Considerable variation in standard heterosis was observed across the 16 traits. For seed yield per plant, standard heterosis ranged from −55.62% to 54.07% over Maya and from −59.46% to 40.75% over Kranti. Vasundhara × PM-26 recorded the highest positive standard heterosis for seed yield per plant over both Maya (54.07%) and Kranti (40.75%). Pusa Bold × Pusa Vijay, Varuna × NPJ-253, Varuna × PM-28, Kranti × NPJ-253, Rohini × PM-28, Maya × Pusa Vijay and Pusa Bold × PM-28 also expressed significant positive heterosis over both checks. Different cross combinations showed desirable heterosis for earliness, reduced plant height, branching, siliquae number, seeds per siliquae, siliquae length, test weight, biological yield and harvest index. The results identify promising hybrid combinations for heterosis-based improvement of Indian mustard. Their performance should be confirmed through multi-location and multi-season evaluation before their use in further breeding or cultivar-development programmes.

Genetic analysis and heterotic potential of onion (Allium cepa L.) for some physiological and agronomic traits under rainy-season cultivation

Onion ( Allium cepa L.) is the second most commonly produced and consumed vegetable worldwide. In West Africa, high heat and moisture are key constraints for onion productivity during the rainy-season. This study aimed to assess the combining ability, heterosis, and genetic variability of five onion genotypes and 10 F 1 hybrids generated through a half diallel mating design to identify superior parental lines and hybrids adapted to heat and moisture conditions. The experiment involved five parents: Prema 178, EW001, Violet d’Abéché, Violet de Galmi and AC980. The trials were implemented on station at the World Vegetable Center in Samanko by using a randomized complete block design. Twelve morphological, physiological, and agronomic traits were evaluated. Analysis of variance showed substantial genetic variability. Significant general combining ability (GCA) and specific combining ability (SCA) effects indicated that both additive and non-additive gene actions influence key traits. The best general combiner was Parent P1 (Prema 178), which had the best positive GCA effects on plant survival rate (5 and 4.98), plant height (2.36 and 2.53), number of bulbs (5.82 and 3.38), and bulb yield (2.09 and 2.44). The hybrids P4×P5 (Violet de Galmi x AC980) and P1xP5 (Prema 178×AC980) had the most positive SCA effects and the best heterosis values over the midparent (105.26%) and better parent (94.56%) for bulb yield, as well as strong vigor and root growth. These results demonstrate that the hybrids P4×P5, P1×P5, and P3×P5 are good candidates for multilocation testing in high heat and high moisture prone conditions.

Heterosis analysis in a full diallel cross of tomato (Solanum lycopersicum L.) for yield and quality traits

Tomato (Solanum lycopersicum L.) is one of the most important vegetable crops worldwide, valued for its nutritional and economic significance. Enhancing yield potential and fruit quality through hybrid development is a key objective in tomato breeding. The present study was conducted at Nauni, Solan (Himachal Pradesh, India) during the summers of 2021 and 2022 to assess the mean performance and heterotic effects of tomato hybrids for yield and quality traits. Seven diverse genotypes were crossed in a full diallel fashion during summer 2021 to develop 42 F₁ hybrids. These hybrids, along with their parents and the standard check Solan Lalima, were evaluated in a randomised complete block design (RCBD) with 3 replications during summer 2022. The results indicated that parental lines Solan Lalima, UHF-T-52, UHF-T-50 and BT-18, as well as crosses Solan Lalima × UHF-T-52, Solan Lalima × UHF-T-50 and UHF-T-52 × Solan Lalima, were superior for yield and its contributing traits. The study highlights the potential of these promising hybrids for developing high-yielding, quality-oriented tomato cultivars. Future breeding programmes can utilise these hybrids as potential parents to introgress desirable alleles and enhance productivity and fruit quality in tomato improvement efforts.  

Efficient Protocol for Doubled Haploid Production in Rye (Secale cereale L.).