Genetic studies on plant, maturity and physiological characters of maize (Zea mays L.) under rainfed and irrigated conditions.

Book Title: NA
Year Published: 2006
Month Published: NA
Author: Rao, M. S. ; Singh, R. D.
Book Group Author: NA
Abstract:

In order to study the gene effects for various morpho-physiological characters related to drought tolerance in maize, generation mean analysis was performed in 3 different crosses and the results are summarized below. Results indicated that mean values (m) were highly significant for all characters studied under rainfed as well as irrigated conditions. Under irrigated conditions, the interaction additive × additive was only found significant for days to 50% tasseling in cross Ib.62 × Ib.37. The type of epistasis was found to be complementary in one cross and it was duplicate in two other crosses studied. Under rainfed conditions, additive effect (d), dominance effect (h) and epistatic effects additive × additive (i) and dominance × dominance effect (l) were significant for the cross Ib.63 × Ib. 128. The type epistasis was found to be complementary in one cross while it was duplicate in nature in other two crosses studied. Dominance effect (h) and epistatic effect additive × additive (i) and dominance × dominance (l) were found significant for days to 50% silking under rainfed conditions. The type of epistasis was both duplicate and complimentary in different crosses studied. Dominance effect (h) was found to be significant in the cross Ib. 62 × Ib.128 while additive effect (d) was found significant for cross Ib.128 × Ib.145. Both additive effect (d) and additive × dominant effect (j) were found significant for cross Ib.62 × Ib. 37. The type of epistasis was duplicate in all the three crosses under rainfed and irrigated conditions. Dominance effect (h) and dominance × dominance interaction (j) were significant in cross Ib.62 × Ib.37 for the character plant height. Epistasis was duplicate in nature. For ear height under rainfed conditions, all the types of gene effects were found to be significant in different crosses studied. The epistasis was of duplicate nature. Dominance effect (h) was found significant in cross Ib.128 × Ib.145 under irrigated condition for number of leaves per plant while under rainfed condition dominance effect (h) and additive × additive effect (i) were significant in cross Ib.62 × Ib.37. The type of epistasis was both complementary and duplicate. Additive effect (d) and dominance × dominance (l) were found for the cross Ib.62 × Ib.37. The type of epistasis was duplicate. For wilt ratings under irrigated conditions, all the gene effects (d,h,i,j and l) were highly significant in the cross Ib.128 × Ib. 145. Under rainfed condition the gene effects were non-significant for wilt ratings and canopy air temperature difference. A perusal of the gene effects revealed that the estimates vary for each cross in different degrees. Significant occurrence of additive, dominance and epistatic components necessitates a breeding methodology like reciprocal recurrent selection or biparental mating or diallele selective mating which would be more useful to improve morpho-physiological characters related to drought tolerance.

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DOI: NA
Keywords:

air temperature, biparental mating, canopy, crosses,dominance, drought resistance, epistasis, genes, genetic variance,irrigation, leaves, maize, maize ears, maturation period, plant height,plant morphology, recurrent selection, Delhi, India, Zea mays, India,South Asia, Asia, Developing Countries, Commonwealth of Nations, Zea,Poaceae, Cyperales, monocotyledons, angiosperms, Spermatophyta, plants,eukaryotes, corn, drought tolerance, hypostasis, leaf canopy, New Delhi,watering, Plant Breeding and Genetics (FF020), Plant Morphology andStructure (FF030), Plant Physiology and Biochemistry (FF060),Environmental Tolerance of Plants (FF900), Soil Water Management(Irrigation and Drainage) (JJ800) (Revised June 2002) [formerly SoilWater Management], Field Crops (FF005) (New March 2000)

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