Genetic divergence studies in bitter gourd (momordica charantia L) genotypes
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Date
2019-08-13
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Vasantrao Naik Marathwada Krishi Vidyapeeth, Parbhani
Abstract
A field experiment “Genetic divergence studies in Bitter gourd (Momordica charantia L.) genotypes. Was carried out at Horticulture Research station (AICRP On Vegetable crops ) ,Vasantrao Naik Marathwada Krishi Vidyapeeth, Parbhani during Kharif , 2018.
The Genetic diversity within Bitter gourd germplasm is a key to the future genentic improvement (Hybridization ) programme . In the present study 40 genotypes of Bitter gourd collected from various institutes and different regions of India were replicated twicely & sown in Randomised blocks with standardized net plot size of 5×1.5 mtrs . And general spacing of 1.5×1mtrs in between the rows and plants respectively during Kharif 2018 at Horticulture research station (AICRP On vegetable crops). In this investigation Results of all the 40 genotypes were analyzed for diversity for 16 morphological characters viz. vine length , number of days for first female flower opening, node number at which first female fower open , number of days taken for first fruit harvest, nuber of branches per plant , Duration of crop, Days to 50% flowering , fruit length , fruit diameter, Average fruit weight, number of fruits per vine , fruit yield per vine , fruit yield per hectare , number of seeds per fruit , flesh thickness, Ascorbic acid content using Mahalanobis D2 statistics are illustrated below.
Multivariate analysis (D2 statistic) given by Mahalanobis‟s was used to group the 40 bitter gourd genotypes into 6 clusters. A maximum of 32 genotypes entered in cluster I, followed by 4 genotypes in cluster II. The cluster III, IV, V and VI had single genotypes each.
The highest intra cluster distance (D2 values) was observed in cluster II (104.02) followed by cluster I (96.08). The Maximum inter cluster distance was observed between cluster II and VI (1620.05) followed by cluster IV and cluster VI (1262.95), cluster II and cluster V (1098.44) and cluster II and cluster III (851.00). This indicates, the genotypes belong to these clusters are more diverse and hence, hybridization between genotypes of respective clusters may improve the yield and quality traits in bitter gourd.
The number of genotypes per cluster varied from 1 - 32. This wider genetic variability may be due to the adaptation of these genotypes to specific environmental conditions. Among the 15 characters studied for D2 analysis, ascorbic acid contributed the maximum (37.31%) to the genetic diversity followed by fruit length (15.64%), frui diameter (14.36%), flesh thickness (11.92%), number of seeds per fruit (9.49%) and days to first female flower opening (6.92%).
The PCV was higher as compared to GCV for all the characters. This indicates that the environment played a major role in the expression of these traits. The high (> 20%) GCV and PCV were observed for fruit length, average fruit weight, number of seeds per fruit, fruit yield per vine and flesh thickness. It indicates existence of broad genetic base, which would be amenable for further crop improvement.
Moderate GCV and PCV (10-20%) was observed for number of branches per vine and fruit diameter which indicates more variability in these characters.
The high estimates of heritability (above 60%) coupled with high values of GAM (more than 20%) were observed for characters viz., fruit length, fruit diameter, number of seeds per fruit, flesh thickness, fruit yield per vine, fruit yield per hectare, average fruit weight, vine length and number of branches per vine. This indicates predominance of additive component for these characters and they are more reliable for effective selection to improve the yield of bitter gourd.
High heritability (> 60%) coupled with moderate to low values of GAM (< 20%) were obtained for days to first female flower opening and ascorbic acid indicated that prevalence of non-additive components and there can be little response to selection and these traits can be exploited through heterosis breeding.
Moderate to low heritability (< 60%) coupled with high GAM (> 20%) were observed for node at which first female flower appears. This indicates the importance of additive gene effects for these traits and there can be better response to selection.
Moderate to low heritability (< 60%) with moderate to low values for GAM (< 20%) were observed for duration of crop, days to 50 per cent flowering, days to first fruit picking and number of fruits per vine. These results elucidate prevalence of non-additive components and higher influence of environments on these traits and hence, selection would be ineffective.
Fruit yield per vine was highly significantly and positively associated with vine length, number of branches per vine, duration of crop, node at which first female flower appears, days to 50 per cent flowering, days to first fruit picking, fruit length, fruit diameter, average fruit weight, number of seeds per fruit and flesh thickness at phenotypic and genotypic levels. This indicated that direct selection for these characters might be effective and there is a possibility of improving yield per vine through selection based on these traits.
The characters viz., fruit length, fruit diameter, duration of crop and average fruit weight are important characters to be accounted for gaining improvement in fruit yield per vine since, these characters had high positive direct and indirect effects on fruit yield per vine.
Thus the Maximum inter cluster distance observed between cluster II and cluster IV followed by cluster IV and cluster V and cluster II and V. This indicates, the genotypes belonging to these clusters are more diverse and hence, hybridization between genotypes of respective cluster may improve the yield and quality of bitter gourd.
The characters viz., fruit length, average fruit weight, number of seeds per fruit, fruit yield per vine, fruit yield per hectare and flesh thickness were recorded high GCV, PCV, heritability and GAM. Hence, these characters had lot of variability with additive gene actions. Therefore, these traits can be improved by simple selection.
Fruit yield per vine was positively and significantly associated with fruit length, fruit diameter, duration of crop and average fruit weight. These characters have to be considered while selecting the genotypes for fruit yield per vine. These characters also recorded high direct effect on fruit yield per vine.
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