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Author: ADHI SHANKAR ×

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    ThesisItemOpen Access
    STUDIES ON HETEROSIS, COMBINING ABILITY AND STABILITY FOR YIELD AND ITS COMPONENTS IN TOMATO (Solanum lycopersicum L.).
    (HORTICULTURAL COLLEGE AND RESEARCH INSTITUTE, VENKATARAMANNAGUDEM, WEST GODAVARI – 534 101 Dr. Y. S. R. HORTICULTURAL UNIVERSITY ANDHRA PRADESH, 2016-06-18) ADHI SHANKAR; R.V.S. K. REDDY
    The present investigation “Studies on heterosis, combining ability and stability for yield and its components in tomato (Solanum lycopersicum L.)” was carried out during 2013-14 of rabi, kharif and summer at Vegetable Research Station, Rajendranagar, Hyderabad to study heterosis, combining ability, stability, genetic parameters, correlation and path analysis for yield and its contributing traits. Six parents LE-53, LE-62, LE-64, Arka Alok, Arka Meghali and Arka Vikas were crossed in diallel mating design. The resultant 30 F1’s were evaluated along with their parents and two standard checks (Lakshmi and US- 618) for sixteen characters viz., plant height (cm), number of primary branches per plant, days to 50% flowering, number of flowers per cluster, number of fruits per cluster, fruit set (%), days to first fruit harvest, days to last fruit harvest, fruit length (cm), fruit width (cm), average fruit weight (g), fruit yield per plant (kg), TSS (0Brix), lycopene (mg/ 100g) and shelf life (days). A perusal of pooled per se performance revealed that hybrids viz., ArkaVikas × Arka Meghali (3.41 kg), Arka Meghali × LE-64 (3.36 kg), Arka Vikas × Arka Alok (3.06 kg), Arka Meghali × Arka Vikas (2.93 kg) and Arka Vikas × LE-53 (2.92 kg) were the most promising, superior crosses for fruit yield per plant and other desirable traits over checks, US-618 (2.30 kg) and Lakshmi (2.79 kg). The ratios of GCA/ SCA variances was less than unity in pooled analysis indicating predominant role of non-additive gene action for all the characters under study. It indicated that the predominance of non additive gene action over the additive gene action is ideal for exploitation through heterosis breeding and recombination breeding with postponement of selection at later generations in tomato. Combining ability analysis revealed that among the parents, LE-62 and LE- 64 were found to be good general combiners for earliness viz., days to 50 per cent flowering and days to first fruit harvest. The parents, Arka Meghali and Arka Vikas were found to be good general combiners for fruit yield per plant and its components. The hybrids, Arka Alok × LE-62 and LE-62 × Arka Alok were found to be good specific combiners for earliness. While the hybrids, Arka Vikas × Arka Meghali (H × H), Arka Vikas × Arka Alok (H × L), Arka Vikas × LE-53 (H × L), LE-64 × Arka Meghali (L × H), Arka Meghali × Arka Vikas (H × H) and LE-64 × LE-62 (L × L) which recorded positively significant sca effects for fruit yield per plant. Hence, these crosses were considered as good specific combiners. Therefore, these hybrids could be recommended for heterosis breeding. The highest standard heterosis for fruit yield per plant over check hybrids (Lakshmi and US-618) was recorded by hybrid Arka Vikas × Arka Meghali followed by Arka Meghali × LE-64, Arka Vikas × Arka Alok, Arka Meghali × Arka Vikas and Arka Vikas × LE-53 along with high per se performance and sca effects. These hybrids may be further exploited in multi location evaluation before releasing them for commercial cultivation. Estimation of genetic parameters revealed that the PCV values were higher than the respective GCV for all the characters denoting influence of environmental factors on their expression. Moderate genetic advance as per cent of mean with high or moderate heritability recorded by yield per plant and shelf life suggested that the action of both additive and non-additive genes there by favorable influence of environment in the expression of the traits.The selection for these traits may not be rewarding and it could be exploited through manifestation of dominance and epistatic components through heterosis. Study of correlations revealed that yield per plant was positively correlated with no. of primary branches per plant, no. of fruits per plant, fruit set, fruit length, fruit width, average fruit weight, days to last fruit harvest and shelf life whereas, it was significant and negatively associated with no. of fruits per cluster, days to first fruit harvest and TSS (0Brix). Path coefficient analysis revealed that days to 50% flowering exhibited the largest direct effect on fruit yield per plant followed by days to last fruit harvest, fruit set, number of fruits per cluster, fruit length, no. of primary branches per plant and fruit width. Results of stability analysis revealed that the hybrids viz., Arka Vikas × Arka Meghali, Arka Meghali × LE-64, Arka Vikas × Arka Alok, LE-62 × LE-53, LE-64 × Arka Meghali, Arka Meghali × Arka Alok and LE-62 × Arka Meghali were identified as stable and best performing hybrids for fruit yield per plant and other traits hence, suitable for wider environments. Among the parents, LE-62 was the stable with high per se performance for yield per plant. Keeping in view of the above facts, by considering all factors like per se performance, sca effects, standard heterosis over Lakshmi and US-618 and stability, the most promising hybrids identified were Arka Vikas × Arka Meghali, Arka Meghali × LE-64, Arka Vikas × Arka Alok, Arka Meghali × Arka Vikas, Arka Vikas × LE-53. These hybrids may be further tested over locations and seasons before recommending for commercial cultivation.
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    ThesisItemOpen Access
    EXPLOITATION OF HETEROSIS FOR YIELD AND QUALITY IN TOMATO (Lycopersicon esculentum Mill.)
    (ANDHRA PRADESH HORTICULTURAL UNIVERSITY, 2010-12) ADHI SHANKAR; Dr. R.V.S.K. REDDY
    The present investigation “Exploitation of heterosis for yield and quality in tomato (Lycopersicon esculentum Mill.).” was carried out during rabi 2009-10 and summer 2010 at Vegetable Research Station, Rajendranagar, Hyderabad to study the heterosis, combining ability, gene action governing the inheritance of the traits and genetic parameters. Eight lines (EC-165749, EC-157568, EC-164838, EC-163611, LE-53, LE-56, LE-62 and LE-64) were crossed with three testers (Arka Alok, Arka Meghali and Arka Vikas) in line x tester mating design. The resultant 24 F1’s were evaluated along with their parents and two standard checks (Lakshmi and US-618) for sixteen characters viz., plant height (cm), number of primary branches per plant, days to 50% flowering, number of flowers per cluster, number of fruits per cluster, fruit length (cm), fruit width (cm), average fruit weight (g), yield per plant (kg), number of locules per fruit, pericarp thickness (mm), TSS (0Brix), titrable acidity (%), ascorbic acid (mg/100g), lycopene(mg/100g) and shelf life (days). Combining ability analysis revealed that magnitude of sca variance was greater than gca variance suggesting the predominance of non-additive gene action for yield per plant, pericarp thickness, TSS, titrable acidity, lycopene and shelf life. The magnitude of degree of dominance revealed over dominance is the cause of heterosis for these traits. Based on gca effects of parents, the lines LE-53 and LE-62 and the tester Arka Alok were good general combiners for most of the traits. The cross combinations EC-157568 x Arka Vikas, EC-163611 x Arka Alok, LE-62 x Arka Alok and LE-64 x Arka Vikas were found to be superior for yield per plant. For quality traits, the cross EC-165749 x Arka Alok was superior specific combiner for yield per plant, TSS, ascorbic acid and shelf life and the cross EC-157568 x Arka Alok was superior specific combiner for TSS, titrable acidity and lycopene. Studies on heterosis revealed that majority of the hybrids exhibited relative heterosis, heterobeltiosis, standard heterosis in desirable direction. The hybrids exhibiting high per se performance also showed high standard heterosis. The cross combination LE-62 x Arka Vikas registered high negative standard heterosis (i.e. for earliness) for days to 50% flowering. The potential crosses like LE-64 x Arka Vikas (H x L), LE-53 x Arka Alok (H x H0, LE-53 x Arka Meghali (H x H), LE-64 x Arka Meghali (H x H), LE-62 x Arka Alok (H x H) exhibited high standard heterosis and high per se performance for yield per plant, which offers scope of commercial exploitation through heterosis breeding. Among promising hybrids for yield per plant, the crosses LE-53 x Arka Alok for TSS and titrable acidity, LE-53 x Arka Meghali for titrable acidity and lycopene and LE-64 x Arka Meghali for titrable acidity and ascorbic acid showed significant standard heterosis. Hence, these are appreciable for processing purpose. The genetic variability studies indicated that genetic material in the present investigation possessed variability which provides sufficient basis for selection by breeder. High estimates of PCV and GCV were obtained for plant height, number of fruits per cluster, average fruit weight, yield per plant, titrable acidity, ascorbic acid and lycopene indicated a good deal of variability in those characters signifying the effectiveness of selection of desirable types for improvement. High heritability assisted with high genetic advance as per cent of mean was observed for plant height, number of primary branches per plant, number of fruits per cluster, fruit length, fruit width, average fruit weight, number of locules per fruit, pericarp thickness, titrable acidity, ascorbic acid, lycopene and shelf life. Hence, simple selection based on phenotypic performance of these traits would be more effective.