GENERATION MEAN ANALYSIS FOR YIELD AND ITS COMPONENT TRAITS IN BOTTLE GOURD.
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Date
2017-07-11
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Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola.
Abstract
The investigation entitled, “Generation mean analysis for yield and its component traits in bottle gourd” was conducted at Main Garden, Department of Horticulture, Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola (M.S.), India during summer 2012, summer 2013 and summer 2014 to know the heterosis and inbreeding depression, gene action and gene interactions, heritability and genetic advance in bottle gourd for sixteen characters viz., vine length, internodal length, node at which first female flower appeared, days to first female flower, sex ratio (M:F), fruit set (%), days to first fruit harvest, number of fruits/vine, average fruit weight, yield/vine, yield/hectare, fruit length, fruit diameter-pedicelar, fruit diameter-central, fruit diameter-stylar and number of seeds/fruit.
The experimental material consisted of five genetically diverse parents viz., P1(Samrat), P2(Arka Bahar), P3(PSPL), P4(DBG-5) and P5(Pusa Samrudhi); their six F1S’ viz., cross C1(P1XP4), C2(P1XP5), C3 (P2XP4), C4(P2XP5), C5(P3XP4) and C6(P3XP5); their respective six F2s’ and back crosses in both directions (six BC1s and six BC2s) were evaluated in randomized block design with three replications using ‘Warad’ as a check.
Parents P1(Samrat), P2(Arka Bahar), P4(DBG-5) and P5(Pusa Samrudhi) with superior per se performance contributed for improved hybrid vigour in their progeny. All the six crosses viz., C1(P1XP4), C2(P1XP5), C3(P2XP4), C4(P2XP5), C5(P3XP4) and C6(P3XP5) exhibited considerable heterosis over respective better parents. Cross C1(P1XP4) and C2(P1XP5) showed useful heterosis over check for yield and yield contributing traits along with excellent fruit characters. The segregating and backcross populations of these crosses found with reduced hybrid vigour and yield, which was evidence of non-additive gene action.
Three parameter model was used to estimate gene effects where non-allelic gene interactions were found absent i.e. for internodal distance (in cross C1, C3 & C5), node at which first female flower appeared (in C3 & C4) and average fruit wt. (in C6). In rest of the characters of six crosses non-allelic gene interactions were present.
In purview of gene action viz, additive, dominance and gene interactions like additive x additive and dominance x dominance, their magnitude differed significantly for studied characters in six crosses. Duplicate type of epistasis was prevalent whereas complimentary epistasis found for few characters like fruit length (in cross C1, C2, C4 & C6), and no. of seeds per fruit (in C6 & C2).
In all the six crosses, the traits like, fruit set (%), no. of fruits/vine, average fruit wt., yield/vine and yield/ha showed strong inclination towards adoption of heterosis breeding for improvement. The character like days to first fruit harvest can be expoited using both heterosis breeding (in C1, C2, C3, C5 & C6) and synthetic varietal breeding (in C4) for early harvest.
Heritability and genetic advance investigation revealed, non-additive gene effect for vine length, internodal distance, node at which first female flower appeared, yield/vine and yield/ha for which heterosis breeding can be taken up. Both additive as well as non-additive gene effects were present in equal proportion for characters viz., days to first female flower, fruit set % and days to first fruit harvest; selection as well as heterosis breeding for improvement of these characters may be considered.
Description
In India, there is a wide range of genetic variability available in bottle gourd but not much attention has been given to the genetical studies and crop improvement except hybrids like Pusa Meghdoot, Pusa Manjari and few varieties by different research institutes. F1 hybrids like Pusa Meghdoot and Pusa Manjari were found a limited use with cultivators especially due to their excessive vegetative growth; low yield and undesirable fruit shape and size viz. long, thin fruits with crook neck in Pusa Meghdoot and flat fruit with depressed stalk-end and large blossom end scar in Pusa manjari. It is an eye which determines the value of the product in market and so, the consumer preference goes with green and tender bottle gourd fruits having 25-30 cm length, cylindrical shape which posses fine pubescence.
Bottle gourd being monoecious is highly cross pollinated crop and offers greater potentialities for exploitation of hybrid vigour. The phenomenon of heterosis has proved to be the most important genetic tool in enhancing the yield of cross pollinated vegetables.
Beside heterosis, bottle gourd a highly cross pollinated and does not suffer much from inbreeding depression thus study of inbreeding depression in F2 may help for varietal development through considering segregating population and using rigorous selection as a tool. It thereby helps farmers through reducing the cost of seeds. High heritability accompanied by a high genetic advance, indicate the predominance of additive gene action, whereas high heritability accompanied by low genetic advance indicate the predominance of epistasis and dominant gene action. High heritability along with high genetic advance is usually more useful in predicting gain under selection than the heritability estimates alone.
It is well known that yield is a complex phenomenon governed by many genes (polygenes); for better understanding of inheritance pattern of such traits, the biometrical technique like generation mean analysis and scaling test are being widely used as they estimate the exact nature and magnitude of the gene action and their interactions if involved. Gene action can vary from one population to another in the same crop and genetic studies are very essential for a given genetic stock before we employ any breeding method for crop improvement.
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Citation
CHAUDHARI, GANESH VASUDEO. (2017). Generation mean analysis for yield and its component traits in bottle gourd. Department of Horticulture, Dr. Panjabrao Deshmukh Krishi Vidhyapeeth, Akola. Ph. D. 2017, Print. xvi, 186p. (Unpublished).