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T. B. Basavaraju , M. R. Gururaja Rao

Abstract

Integration of trees in agroforestry system results in positive or negative interactions between trees and crops. Micro-climate amelioration and maintenance or improvement in soil productivity are the major positive interactions while competition for light, water and nutrients, and allelopathy are the major negative interactions in agroforestry systems. The balance between negative and positive interactions determines the over all effect of interactions in a given agroforestry system. Selection of suitable tree species for agroforestry is important, however many a times it is not possible to select tree species having all the desirable characters for agroforestry because of different production or protection goals. In such situations agroforestry systems have to be managed through planting optimum density of trees, proper spatial arrangement and pruning and thinning of tree crowns and ischolar_mains to reduce the negative effects of trees.

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K. K. Kiran ¹, M. R. Gururaja Rao ¹, K Suresh ¹

Affiliations
1 Department of Genetics and Plant Breeding, University of Agricultural Sciences, G.k.v.k., Bengaluru, Karnataka, IN
2 Department of Genetics and Plant Breeding, University of Agricultural Sciences, G.K.V.K., Bengaluru, Karnataka, IN

Abstract

An investigation was carried out at ZARS, VC Farm, Mandya during 2011-2012 to study the frequency distribution and variability produced in two F₂ populations of rice viz.,'IR 64 BPHR-1' and 'Jaya BPHR-1' for grain yield and its seven component characters. The F₂ populations of both the crosses showed high PCV and GCV values coupled with high heritability and high genetic advance as per cent of mean for total tillers per plant, productive tillers per plant, grains per panicle and grain yield per plant. Skewness and kurtosis indicated dominance based complementary gene interaction involving large number of genes having decreasing effect in the inheritance of total tillers per plant, days to panicle emergence, productive tillers per plant, grains per panicle and grain yield in both the crosses and for 1000-grain weight in 'Jaya BPHR-1'. However, duplicate interaction was noticed for panicle length in both the crosses; while, 1000-grain weight showed complete ambi-directional epistasis in the cross 'IR 64 BPHR-1'.Contrary to this, plant height exhibited dominance based complete interaction for few segregating genes with majority of them having decreasing effect.

Keywords

Frequency Distribution, Gene Interaction, F₂ Population, Pcv, Gcv

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J. Shanthala ¹, M. R. Gururaja Rao ¹, E. Gangappa ¹, P. Venkataravana ¹

Affiliations
1 Department of Genetic and Plant Breeding, College of Agriculture, University of Agricultural Sciences, G.K.V.K., Bengaluru, Karataka, IN

Abstract

An experiment to study the effectiveness of -rays and ethyl methane sulphonate induced mutagenesis in bringing about shift in mean and creation of genetic variability for pod yield and its attributes in two varieties of groundnut viz., GPBD-4 and CTMG-1 and their _F2 and F₂M₂ generations was carried out during 2006-08, at Agricultural Research Station, Chintamani, UAS (B). The LD₅₀ dose was fixed at 20 kR for gamma ray irradiation and at 0.5 per cent for ethyl methane sulphonatee (EMS). The two varieties exhibited differential response to different mutagens. In general, the overall shifts in the mean of F₂M₂ population was maximum in the desirable directions compared to any other populations followed by 20 kR irradiated M₂ population of CTMG-1. The F₂M₂ population manifested maximum heritability (96.44%) and genetic advance as per cent of mean (76.24%) and among the mutagen treated M₂ populations, maximum heritability (81.35 %) and genetic advance as per cent of mean (41.50%) was recorded in 20 kR irradiated populations of GPBD-4 for pod yield (g/plant). The mutagenic treatment with 20 kR irradiated and 0.5 per cent EMS treated GPBD-4 and CTMG-1 populations and F₂M₂ population have resulted in creation of higher genetic variations and hence serve as an excellent source material for variety development representing a more efficient source of genetic variability than gene pools conserved by nature.

Keywords

Induced Mutagenesis, Shifts in Mean, Genetic Variability, F₂m₂ Population

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H. B. Dinesh ¹, M. R. Gururaja Rao ¹, S. Ramesh ¹, A. Mohan Rao ¹, S. J. Satheesh Naik ¹, Sidramappa Talekar ¹

Affiliations
1 Department of Genetics and Plant Breeding, University of Agricultural Sciences, G.K.V.K., Bengaluru, Karnataka, IN

Abstract

Influence of male sterility inducing cytoplasm on heterosis with respect to ethanol yield and its attributing traits in sweet sorghum was studied in 48 hybrids developed by crossing six A- lines viz., ICSA 631, ICSA 731, ICSA 324, ICSA 500, ICSA 38 and ICSA 84 and their corresponding B- lines with four R- lines viz., SEREDO, ICSV 700, ICSV 111 and E 36-1 in a line × tester mating design. The 16 parents and their 48 hybrids were grown separately in contiguous blocks in single row of 3m length with 0.15 m × 0.60 m spacing in simple lattice design with two replications at the experimental plots of Gandhi Krishi Vignana Kendra (GKVK), University of Agricultural Sciences (UAS), Bangalore. Presence of an average level of heterosis for all the traits studied were evident as exemplified by significant mean squares due to parents vs. hybrids. While cytoplasmic influence was apparent for midparent heterosis under individual nuclear genetic background for all the traits, no definite trend favoring any particular cytoplasm was observed.

Keywords

Cytoplasmic Influence, Heterosis, Male Sterility Inducing Cytoplasm, Sweet Sorghum

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R. Vinay Kumar ¹, B. N. Jagadeesh ¹, Sidramappa Talekar ¹, M. R. Gururaja Rao ¹

Affiliations
1 Department of Genetics and Plant Breeding, Agricultural College, University of Agricultural Science, G. K.V.K., Bengaluru (Karnataka), IN

Abstract

An investigation was carried out to assess the nature of combining ability and gene action in respect of bio-energy traits in 72 new hybrids of sweet sorghum developed by crossing 4 male sterile lines and 18 testers in line × tester mating design and grown in Randomized Block Design with two replications during Kharif 2008 at ‘K’ Block of Zonal Agricultural Research Station, University of Agricultural Sciences, GKVK, Bengaluru. The variance among the lines (for juice yield and total sugars), testers (for juice yield) and line × tester interaction (for all the characters studied) in respect of their general combining ability were highly significant indicating predominance of non-additive gene action in genetic control of these traits. ICSA 84, ICSA 38 and ICSA 264 among the lines and NTJ 2, E 36-1 and GD 65008 among the testers, were identified as good general combiners indicating their ability in transmitting additive genes in the desirable direction to their progenies. Highly significant sca effects were observed for all the characters studied and good specific combiners for different characters involved parents with high × high, high × low, low × high and low × low general combinations.

Keywords

Sweet sorghum, Bio-energy traits, Combining ability.

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