GENETIC VARIABILITY, CORRELATION AND PATH COEFFICIENT ANALYSIS IN GARLIC (Allium sativum L.) 2419
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Date
2017-08
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JAU,JUNAGADH
Abstract
Key words: Garlic, traits, analysis of variance, variability, heritability, correlation, path analysis
The present study was carried out to assess genetic variability, correlation coefficients and path coefficient analysis in 156 genotypes and 4 checks of garlic grown in Augmented Randomized Block Design at Vegetable Research Station, Junagadh Agricultural University, Junagadh during rabi season of 2015-2016. The observations were recorded on 21 characters viz., plant height (cm), number of leaves per plant, leaf length (cm), leaf width at middle portion (cm), days to maturity (days), pseudostem height (cm), collar thickness (cm), bulb collar diameter (cm), bulb equatorial diameter (cm), bulb polar diameter (cm), bulb weight (g), number of cloves per bulb, clove weight (g), clove length (cm), clove polar diameter (cm), clove equatorial diameter (cm), total soluble solids (%) and bulb yield (kg/ha), anthocyanin pigmentation, bulb shape, bulb colour.
The analysis of variance revealed that mean squares due to genotypes were significant for all the traits except plant height, days to maturity indicating the presence of sufficient amount of genetic variability among the genotypes. Based on mean values with respect to characters, the genotype RGP-447 was the higher yielder followed by RGP-108, RGP-56, JGP-183 and RGP-384. The genotype RGP-447 was the top genotypes for the economic trait such as bulb weight. These genotypes might be utilized in further breeding programme for improvement in bulb yield.
The value of the phenotypic coefficient of variation was higher than the corresponding genotypic coefficient of variation for all the characters which indicated effect of environment on the character expression. The GCV and PCV were higher for clove weight, bulb weight and bulb yield. Moderated GCV and PCV were observed for pseudostem height, clove equatorial diameter, number of cloves per bulb, bulb collar diameter, number of leaves per plant, leaf width at middle portion, collar thickness, leaf length, bulb polar diameter, clove polar diameter, clove length, bulb equatorial diameter, plant height. While bulb polar diameter, clove polar diameter, leaf length, clove length, bulb equatorial diameter, plant height, total soluble solids, days to maturity showed low GCV and PCV.
High estimates of heritability was recorded for total soluble solids, clove weight, pseudostem height. Moderate heritability was obtained for clove equatorial diameter, bulb yield, bulb weight, number of leaves per plant, clove polar diameter, bulb polar diameter, leaf width at middle portion. Low value of heritability was recorded for bulb equatorial diameter, clove length, number of cloves per bulb, leaf length, bulb collar diameter, collar thickness, plant height and days to maturity. These characters would be effective in selection for garlic improvement. The genetic advance at 5% selection intensity (k=2.06) was found high for bulb yield followed by total soluble solids, bulb weight. Moderate genetic advance was observed for leaf length, pseudostem height, plant height, number of leaves per plant, number of cloves per bulb, while remaining all the traits, days to maturity, bulb polar diameter, clove weight, bulb equatorial diameter, clove polar diameter, clove equatorial diameter, leaf width at middle portion, clove length, bulb collar diameter and collar thickness exhibited the low genetic advance.
A wide range of expected genetic advance as per cent of mean was observed for different characters. High estimates of genetic advance as per cent of mean was reported for the characters viz. clove weight, bulb weight, bulb yield, pseudostem height, clove equatorial diameter, number of leaves per plant, number of cloves per bulb, leaf width at middle portion, bulb collar diameter. High heritability along with high genetic advance as per cent of mean was observed for clove weight and pseudostem height. In this condition selection will be more effective for these characters might be under the control of additive gene effects. On the other hand low heritability with low genetic advance as per cent of mean was observed for bulb equatorial diameter, clove length, plant height and days to maturity.
In general, the estimates of genotypic correlation were higher than the corresponding phenotypic correlation coefficient. It may result from the modifying effect of environment on the association of characters at genotypic level. The bulb yield was significant and positive correlation with characters like with plant height, number of leaves per plant, leaf width at middle portion, pseudostem length, bulb collar diameter, bulb equatorial diameter, bulb polar diameter, bulb weight and clove length, clove polar diameter and clove equatorial diameter. From these associations, it appears that higher bulb yield can be obtained by improving these characters.
Path coefficient analysis revealed that the characters like plant height and clove polar diameter had high direct effect on bulb yield. These above characters also had positive indirect effect on each other. Plant height, number of leaves per plant, leaf width at middle portion, pseudostem height exhibited positive and indirect effects on bulb yield via plant height, leaf length, leaf width at middle portion, days to maturity, pseudostem height, bulb equatorial diameter, bulb polar diameter, bulb weight, number of cloves per bulb, clove weight and clove polar diameter, clove equatorial diameter and total soluble solids. Bulb collar diameter, bulb equatorial diameter, bulb polar diameter, bulb weight, clove length, clove polar diameter and clove equatorial diameter contributed indirectly by giving positive indirect effects on bulb yield through plant height, leaf width at middle portion, bulb equatorial diameter, bulb polar diameter, bulb weight, number of cloves per bulb, clove polar diameter, clove equatorial diameter and total soluble solids.
The final conclusion that can be reached from variability, correlations and path coefficient analysis, it can be concluded that for yield improvement in garlic; plant height, number of leaves per plant, leaf length, pseudostem height, bulb collar diameter, bulb equatorial diameter, bulb polar diameter, bulb weight, number of cloves per bulb, clove weight, clove length, clove polar diameter, clove equatorial diameter were most important component characters. Hence, these traits should be considered as selection criteria for yield improvement in garlic.
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PLANT BREEDING