Genetic variability Studies on some Indigenous Cultivars of Assam under Organic and Conventional Cultivation Method

Author: Lonishree Dutta, K.K. Sharma and Dibosh Bordoloi

Download PDF

Abstract

A field experiment was carried out with 11 genotypes of indigenous Assam rice cultivars collected from Kakopothar, Tinsukia District where rice cultivation is practiced organically for more than 10 years. The experiment was conducted under organic and conventional condition at Instruction cum Research Farm of Department of Plant Breeding and Genetics, Assam Agricultural University, Jorhat, Assam, India to study the variability and genetic parameters for yield and its components and grain quality traits. Variance analysis displayed extensive traits-wise variations across accessions, indicating variability and the opportunity for genetic selection for desirable traits. The studies on genetic variation and its understanding in indigenous cultivars of Assam rice (Oryza sativa L.) can help to select varieties for organic cultivation. The investigation revealed that the estimates of pooled GCV for all the characters studied were slightly less than pooled PCV estimates indicating the influence of the environment on the genotype performance. The traits ear-bearing tiller, thousand-grain weight, grains per panicle, grain length, grain length by breadth ratio, kernel length, kernel breadth, harvest index, and grain yield per hectare all showed moderate to high variability, high heritability coupled with high genetic advance as percent of mean indicating the role of additive gene effect and simple selection procedures may be effective for improving these traits. Low PCV and GCV were recorded for the traits viz., days to 50% flowering, hulling percentage, and milling percentage. High heritability coupled with low genetic advance as percent of mean was observed for days to 50% flowering, hulling percentage and milling percentage indicating the role of both additive and non-additive gene effects in the inheritance of these traits.

Keywords

Analysis of variance, genetic advance, heritability, additive gene effect, non-additive gene effect

Conclusion

The study concluded that significant yield-attributing traits such as the ear-bearing tiller, thousand-grain weight, grains per panicle, grain length, grain length by breadth ratio, kernel length, kernel breadth, harvest index, and grain yield per hectare all exhibited moderate to high variability, high heritability, along with high genetic advance as a percentage of mean, indicating the predominant role of additive gene action. For most of the characters where PCV and GCV are of higher magnitude, improvement in varieties can be achieved through direct selection. This indicates that these characters will respond to selection in both the growing conditions. PCV and GCV were low in case of hulling per cent, milling per cent and HRR while heritability estimate was found to be high. Therefore, these characters are least influenced by environment. So, the breeder can perform selection based on the phenotypic expression of the characters. Jahinga Sali was found to be early flowering type as compared to other traditional varieties under study. Plant height was found to be higher in conventional situation than organic due to high fertilizer intake. From the study, ear bearing tiller and panicle length can be increased in organic situation by application of organic fertilizers which is a direct component towards achieving higher yield. Flag leaf area of varieties like Kola Joha, Kola Sali, Nekera Lahi, and Malbhog Lahi were found to be highest and is at par under both the growing condition. Thus, character improvement could be taken either in organic and conventional situations. Solpona exhibited higher grains per panicle in organic conditions than conventional, indicating that the variety could be taken as parents for hybridization in organic situations. Given the high demand for organic food in domestic and international markets, grain characteristics play an important role. Thus, from the study, Beji Lahi was found to be a promising genotype for its long and slender grain quality and good head rice recovery. This reveals that for executing a breeding program for improvement of grain quality Beji Lahi could be an ideal variety. The study indicated that Kola Joha and Kola Sali were found to have head rice recovery to the tune of 98 percent in organic situations. Such varieties may be used as donors for head rice recovery in breeding programs under organic situations. Solpona is a rice variety which is having higher hulling percentage in organic conditions. This indicates that Solpona can be a parent in hybridization for the improvement of grain characters in organic situations.

References

-

How to cite this article

Lonishree Dutta, K.K. Sharma and Dibosh Bordoloi (2023). Genetic variability Studies on some Indigenous Cultivars of Assam under Organic and Conventional Cultivation Method. Biological Forum – An International Journal, 15(10): 174-181.