Selection of suitable genotypes of linseed (Linum usitatissimum L.) for rainfed condition

Introduction

Linseed is an important oilseed crop of the tropical as well as temperate region of the world. It is one of the most important industrial oilseed crops of India. Next to rapeseed mustard in terms of cultivation and seed production in India, it is the second most significant Rabi oilseed crop. There are over 230 species in genus linum, but only one is economically significant and one of the earliest plants framed for fiber and oil is cultivated linseed or flax [Rowland et al. (1995), Tadesse et al. (2010)] [10,14] . Linseed is basically an industrial oilseed crop and its each and every part has got industrial importance. The seeds of linseed contain about 33-45% oil. It is generally unsuitable for domestic purpose due to high linolenic acid content (47-58%) but an excellent source of Omega-3 and Omega-6 fatty acids. Farmers use roughly 20% of the total amount of Linseed oil produced in India. Linseed is extensively cultivated throughout the world including Canada, Russia, and China etc. Globally, linseed is grown in an area of 32.63 lakh ha. accounting of 31.82 lakh tones with an average productivity of 975 kg per hectare (Anonymous, 2019) [1] . Canada is currently the world's leader in the production and export of flax seed and it has held this position since 1994. India ranks 5 th in an area (1.7lakh ha.) and 6 th in production (1.0 lakh ton) with average productivity of 574kg/ha (FAO, stat, 2019) [4] . Four states viz. Madhya Pradesh, Jharkhand and Odisha are the major linseed growing states accounting for 65% of an area and 64% of production, respectively (Anonymous, 2020) [2] . The main reasons for low productivity of linseed in the country are inherent low yielding capacity of existing varieties and late maturity, lack of stability of yield and cultivation of crop under poor agronomic management on marginal lands. The development of superior varieties than the existing ones mainly depends on judicious selection of promising parents from the gene pool for hybridization to obtain transgressive segregants. Thus, for assessing the existing genetic variability among genotypes studied for yield and its contributing characters along with quality parameters was the aim of the present investigation.

Research Procedure

The present investigation was undertaken to obtain information on means, components of genetic variance, heritability and genetic advance for some quantitative and qualitative traits. The materials for the present investigation comprised of nineteen genotypes of linseed and evaluated along with two checks (T 397 & Shekhar) in Randomized Block Design with three replications at Research Farm of TCA, Dholi, Muzaffarpur during Rabi season of the year 2021-22. Recommended package and practices for linseed were adopted to raise good crop under Rainfed condition. Observations were recorded on eight quantitative and qualitative characters i.e. days to flowering, days to maturity, number of capsules per plant, number of seeds per capsule, 1000 seed weight (g), seed yield (kg./ha.), oil content (%) and germination percentage.

Result and Discussion

Analysis of variance revealed that significant genotypic differences were observed for all the traits indicating that there were sufficient genetic variations among all the genotypes under studied presented in table-1. Similar findings were also observed by Tadesse et al. (2010) [14] ; Belate et al. (2013) [3] and Sharma et al. (2016) [13] . Estimate of mean performance of 19 genotypes for eight characters (Table -2) revealed that the highest range was recorded for seed yield (kg./ha) and lowest for 1000-seed wt.(g.).The entry SLS 139 showed significant superiority for the traits like days to flowering, days to maturity, oil content and germination percentage over the best check (T 397). Most of the entries were recorded at par values for the traits no. of capsules per plant, 1000-seed wt. and seed yield (kg./ha.) over the best check i.e. T 397. The estimate of GCV and PCV (table-3) reflects that the PCV values were higher than their corresponding GCV values for all the traits which reflect the influence of environment on the expression of these characters. High values of PCV than their corresponding GCV were also observed by earlier workers [Kumar et al. (2013) [8] and Sahu et al. (2014)] [12] . The moderate GCV values were observed for oil content, seed yield (kg./ha.) and no. of capsules per plant and rest characters showed low GCV values. Moderate GCV values for seed yield were reported by Paul and kumar (2018) [11] . The higher magnitude of PCV was observed for seed yield (kg./ha.) followed by oil content and no. of capsules per plant which was also reported by Tyagi et al. (2014) [15] . Estimates of heritability in broad sense were ranged from 23.20 to 81.20. Maximum heritability were recorded oil content followed by days to flowering, days to maturity and germination percentage. Present result are in agreement with the findings of Nakhlawy (2006) [9] ; Kumar et al. (2012) [7] ; Ahmad et al. (2014) [3] and Tyagi et al. (2014) [15] . High heritability estimates would be rewarding for development of superior genotypes on the basis of phenotypic performance of that particular traits. However, Johanson et al. (1955) [6] reported that h 2 estimates along with genetic advance as percentage of mean were more rewarding than the heritability alone while selecting the best genotypes. High heritability coupled with high genetic advance as percentage of mean was observed for the trait oil content. This demonstrates the presence of additive gene effects indicating more rewarding in selection on the basis of phenotypic performance for oil content.

Conclusion

The estimate of GCV and PCV reflects that the PCV values were higher than their corresponding GCV values for all the traits which reflect the influence of environment on the expression of these characters. Maximum heritability was recorded for oil content followed by days to flowering, days to maturity and germination percentage while High heritability coupled with high genetic advance as percentage of mean was observed for the trait oil content indicating that these traits may be more effective in selection of superior genotypes on the basis of phenotypic performance.

References

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