Heterosis for seed yield, yield contributing traits and β-ODAP content in lathyrus (Lathyrus sativus L.)

Introduction

Lathyrus (Lathyrus sativus L.), commonly known as grass pea, is an important food legume cultivated mainly under rainfed and marginal environments because of its ability to withstand drought and other adverse growing conditions. The crop is valued for its relatively stable performance under moisture-stressed conditions and its contribution to food and nutritional security. However, the presence of the neurotoxic nonprotein amino acid β-N-oxalyl-L-α,β-diaminopropionic acid (β-ODAP) in the seed is a major limitation to its wider utilization as a food and feed crop. Therefore, simultaneous improvement of seed yield and reduction of β-ODAP content remains an important objective in Lathyrus breeding. Genetic improvement of Lathyrus depends on the identification and utilization of genetically diverse parents and superior cross combinations. Heterosis, expressed as the superiority of F 1 hybrids over their parents or a standard check, provides useful information on the magnitude and direction of genetic variation among cross combinations. The estimation of heterosis for yield and its component traits helps in identifying crosses with desirable combinations of characters and can also provide a basis for selecting segregating populations in subsequent generations. In Lathyrus, information on heterosis for yield and its component characters is relatively limited compared with other pulse crops. Previous studies have demonstrated variability among Lathyrus crosses for yield and associated traits and have emphasized the importance of selecting suitable parental combinations for genetic improvement. Heterosis studies are particularly useful for identifying crosses that combine higher seed yield with desirable plant architecture and other agronomic traits. In addition, assessment of heterosis for β-ODAP content can help identify cross combinations showing a desirable reduction in the neurotoxic compound.

The present investigation was therefore undertaken to estimate heterosis over the better parent and a standard check for seed yield, yield contributing traits and β-ODAP content in Lathyrus. The study involved 39 F 1 crosses developed through a line × tester mating design using 13 lines and three testers. The objective was to identify promising cross combinations exhibiting desirable heterosis for seed yield and its contributing traits together with reduced β-ODAP content, which could be utilized in further Lathyrus improvement programmes.

Material and method

The experimental material comprised thirteen lines viz., NLK-6, NLK-42, NLK-37, NLK-56, NLK-102, NLK-49, NLK-74, NLK-73, NLK-38, EC-207071, NLM-12, NLM-17 and NLM-23 and three testers viz., Ratan, Prateek and Mahateora. During rabi 2024-25, the thirteen lines were crossed with three testers following a line × tester mating design to obtain 39 F 1 cross combinations. The resulting F 1 hybrids along with their parents and standard checks were evaluated during rabi 2025-26 at the Research Farm of the Agricultural Botany Section, College of Agriculture, Nagpur. The experiment was conducted in a randomized block design with three replications. The crop was raised following the recommended package of practices. Observations were recorded on five randomly selected plants from each entry for days to first flowering, days to 50 per cent flowering, days to maturity, plant height (cm), number of branches plant -1 , number of pods plant -1 , 100-seed weight (g), seed yield plant -1 (g) and β-ODAP content (%). β-ODAP content was estimated using the dryseed phytochemical assessment method of Briggs et al. (1983) [1] . Analysis of variance for the experimental design was carried out according to Panse et al. (1954) [2] .

Results and discussion

Analysis of variance for experimental design

The analysis of variance for the different characters studied is presented in Table 2. The mean squares due to genotypes were found to be highly significant for all the traits studied namely days to first flowering, days to 50% flowering, days to maturity, plant height, number of branches plant -1 , number of pods plant -1 , 100-seed weight, seed yield plant -1 and ODAP content. The significant differences among genotypes for these characters indicated the existence of substantial genetic variability within the experimental material. The variability observed provides ample scope for effective selection and genetic improvement of these traits in lathyrus. In accordance to this results Lyngdoh et al. (2019) [3] , Nawale et al. (2024) [4] and Singh et al. (2025) [5] also observed significant genotypic variation for important agronomic traits in lathyrus, thereby emphasizing the usefulness of available germplasm for breeding programmes.

Analysis of variance for heterosis

The mean squares due to parents were highly significant for all the characters studied except for plant height and the mean squares due to crosses were highly significant for all the nine traits studied. Further mean squares due to the interaction component of parents versus crosses was also found to be significant for all the characters, demonstrating marked differences between parental lines and their respective hybrids. This indicates the suitability of data for estimation of heterosis over better parent and useful heterosis over Ratan for all nine characters viz. days to first flower, days to 50% flowering, days to maturity, plant height, number of branches plant -1 , number of pods plant -1 , 100-seed weight, seed yield plant -1 and ODAP content in lathyrus. Similar to this result, Wagh (2015) [6] , Sayyad et al. (2017) [7] , Lyngdoh et al. (2019) [3] , and Nawale et al. (2024) [4] also observed significant mean squares due to parent vs. crosses interaction effect for days to first flowering, days to 50% flowering, days to ma-turity, plant height, number of branches plant -1 , number of pods plant -1 , 100-seed weight, seed yield plant -1 and ODAP content. The results on heterosis estimation revealed that considerable heterosis was observed for all the nine characters studied. The magnitude of heterobeltiosis and useful heterosis differed for different characters. The extent of heterosis gives clue of the type of genetic control in the characters. Heterosis by itself, whether over the mid-parent and better parent cannot tell us much about the superiority of the hybrid over the check, which is of practical value for plant breeding and therefore, useful heterosis should be given more emphasis. In this study, significant useful heterosis in the desirable direction was observed for days to maturity in seventeen crosses, plant height in seventeen crosses, number of branches plant -1 in four crosses, number of pods plant -1 in four crosses, seed yield per plant -1 in four crosses, and ODAP content in ten crosses. Seed yield plant -1 , being the most important economic character, showed substantial variation among the crosses. Significant positive heterobeltiosis for seed yield was recorded in only four crosses, namely NLM-23 × Ratan (31.59%), NLM-12 × Ratan (25.99%), NLM-12 × Prateek (24.32%) and NLK-73 × Prateek (16.38%). These crosses also exhibited significant positive useful heterosis over the standard check Ratan, with values of 31.59%, 25.99%, 20.07% and 18.29% respectively. The superior performance of these crosses was accompanied by favourable heterosis for important yield components, particularly branches and pods plant -1 . The results therefore suggest that heterotic expression for seed yield was largely associated with improvement in its component characters. Similar importance of heterosis for yield and associated traits has been reported in Lathyrus by Wagh (2015) [6] , Sayyad et al. (2017) [7] and Lyngdoh et al. (

. An important feature of the present investigation was the estimation of heterosis for β-ODAP content along with yield traits. Since lower β-ODAP content is desirable, negative heterosis was considered favourable. Significant negative heterobeltiosis was recorded in five crosses, with the highest reduction observed in NLK-73 × Ratan (-40.08%), followed by NLM-12 × Ratan (-29.20%) and NLM-12 × Mahateora (-28.51%). Significant negative useful heterosis was observed in ten crosses, indicating substantial scope for reducing β-ODAP content through appropriate hybridization. The occurrence of favourable heterosis for both seed yield and β-ODAP content in selected combinations is particularly important because simultaneous improvement of productivity and reduction of the antinutritional/toxic compound is a major breeding objective in Lathyrus. Considering seed yield together with its component traits and β-ODAP content, NLM-23 × Ratan, NLM-12 × Ratan, NLM-12 × Prateek and NLK-73 × Prateek emerged as the most notable crosses on the basis of significant positive heterosis for seed yield and favourable expression for important yield components. Among these, NLM-23 × Ratan was particularly noteworthy because it recorded the highest heterobeltiosis and useful heterosis for seed yield (31.59%) and also showed positive heterotic expression for branches and pods plant -1 . NLM-12 × Ratan and NLM-12 × Prateek likewise combined high positive heterosis for seed yield with favourable expression of yield components. These results indicate that selection of suitable parental combinations is essential for obtaining heterotic expression for complex quantitative traits. The crosses NLM-23 × Ratan, NLM-12 × Prateek, NLM-12 × Ratan, and NLK-73 × Prateek were found to exhibit positive significant heterosis for seed yield plant -1 , number of pods plant -1 and number of branches plant -1 and negative significant heterosis for days to maturity, plant height and ODAP content. Hence, these four crosses can be identified as promising crosses for further exploitation. The above four crosses recorded high mean performance along with positive significant sca effects, indicating the presence of dominance gene action, which can be exploited for the commercial utilization of heterosis.

Conclusion

The present investigation demonstrated considerable genetic variability and differential heterotic expression among the 39 Lathyrus crosses for flowering, maturity, plant architecture, yield components, seed yield and β-ODAP content. Significant positive heterosis for seed yield was identified in NLM-23 × Ratan, NLM-12 × Ratan, NLM-12 × Prateek and NLK-73 × Prateek, which also showed favourable heterosis for important yield contributing characters, particularly branches and pods plant -1 . Significant negative heterosis for β-ODAP content was observed in several crosses, indicating the possibility of combining higher productivity with reduced β-ODAP content. Among the evaluated combinations, the above crosses may therefore serve as useful breeding material for further generation advancement and selection. The results emphasize the importance of appropriate parental selection for generating useful variability and superior recombinants in Lathyrus improvement programmes.

References

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9. How to cite this article: Bankar SB, Patil SR, Madke VS, Shende P, Wankhede SP, Navale SG, et al. Heterosis for seed yield, yield contributing traits and β-ODAP content in lathyrus (Lathyrus sativus L.). International Journal of Advanced Biochemistry Research. 2026;SP-10(9):2557-2563. doi: https://w ww.doi.org/10.33545/26174693.2026.v10.i9Saf.10215