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Subject: Plant Breeding × End date: 2004 × Start date: 2004 × Type: Thesis ×
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    ThesisItemOpen Access
    Genetic improvement of F1 hybrids in anthurium andreanum linden
    (Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2004) Pravin, R S; KAU; Mayadevi, Department of Plant Breeding and Genetics, College of Agriculture
    The present study, ‘Genetic improvement of F1 hybrids in Anthurium andreanum Linden’ was undertaken to improve specific commercial characters such as erect, long inflorescence axis, deep blisters of spathe and short downward candles of ten selected F1 hybrids in anthurium. The analysis of variance revealed significant variation among the fourteen genotypes for the seventeen characters studied. This reveals the high genetic potential for the improvement in this crop. Variability studies indicated high phenotypic and genotypic coefficients of variation for the characters number of suckers per plant, pollen fertility and duration of male phase. The characters with high heritability coupled with high genetic advance values were found for characters number of suckers per plant, pollen fertility and pollen size. These characters are therefore controlled by additive gene action and amenable to genetic improvement through selection. Plant height was found to have highly significant positive phenotypic correlation with number of suckers per plant, leaf size, internode length, number of spadices per plant and pollen fertility. Duration of female phase showed positive genotypic correlation with all characters except days to initiation of female phase. The environmental correlations were absent for almost all pairs of characters except for a few characters . Pollen fertility estimated using acetocarmine method indicated that most of the genotypes had low fertility values. ‘PR x FR (1)’ had the highest pollen fertility of 41.67 per cent followed by ‘Liver Red’ (40.67 per cent). Pollen emergence was low in the months from March to June, during which the average maximum and minimum temperatures were relatively high. Pollen emergence was highest during October to December months. A study of five qualitative characters such as colour of young leaf and petiole spathe colour, spathe texture, candle colour and type of inflorescence axis also showed considerable variation among the genotypes studied. Intervarietal hybridization was done to analyse the cross compatibility between 14 varieties (Ten female parents and four commercially important varieties as male parents) based on the percentage of candles bearing fruits, fruit set and seed germination. A total of 23 crosses were attempted based on the availability of receptive spadices and fresh pollen, out of which 12 were found to be successful. Among the 12 successful crosses percentage of candles bearing fruits was 100 per cent for six crosses. Maximum number of 113 fruits was obtained for the cross (‘LR x PR’) x OG followed by [‘FR x MW (1)’] x LR with 88 fruits. The average number of fruits per candles was highest for ‘LR x PR’ and lowest for ‘PR x FR (1)’. The percentage of fruit set was below 50 per cent for all the crosses. The lowest and highest percentage of fruit set was observed for ‘PR x FR (1)’ and ‘LR x PR’ respectively. From the cross compatibility analysis, it was seen that the percentage of fruit bearing candles was highest for the female parents ‘PR x KR’ and ‘PR x MO’ with two crosses each and ‘OG x DT’ with a single cross (100 per cent). The number of fruit per candle ranged from 23 to 113. ‘LR x PR’ had the highest average number of fruits per candle and it was lowest for ‘PR x FR (1)’. The percentage of fruit set was below 50 per cent for all the crosses. The crosses involving ‘LR x PR’ had the highest average percentage of fruit set. The number of days taken for germination varied from four to nine days. The seed germination was highest for the cross (‘PR x FR(1)’) x LR (85.13 per cent). No cross showed 100 per cent survival beyond four to six months. For ‘OG x DT’ with only a single cross the survival percentage was maximum of 90 per cent. Scoring of the compatibility reactions based on the percentage of fruiting candles, fruit set and seed germination on a scale ranging from zero to nine showed the highest compatibility score of eight for the crosses (‘PR x KR’) x AW, (‘LR x PR’) x OG, (‘PR x MO’) x LR and (‘PR x MO’) x AW. Among the ten female parents ‘PR x MO’, ‘LR x PR’ and ‘PR x KR’ performed as the best female parents and among the four male parents ‘Liver Red’ performed as the best pollen parent.
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    ThesisItemOpen Access
    Genotype x environment interaction in commercial rice (Oryza sativa L.,) hybrids
    (Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2004) Somanagoudra S, Chandrashekhar; KAU; Elsy, C R
    The present study on “Genotype x Environment interaction in commercial rice (Oryza sativa L.) hybrids” was carried out under the Department of Plant Breeding and Genetics, College of Horticulture, Kerala Agricultural University, Vellanikkara. Seven commercial rice hybrids and two check varieties were evaluated for eighteen characters across three farming situations of central zone of Kerala during kharif, 2003. In the experiment, variability, heritability and genetic advance, path coefficients, stability, standard heterosis and inbreeding depression were estimated. Mean performance of hybrids across the locations revealed that, in general hybrids performed better than check varieties with respect to yield and yield attributing characters like grain yield ha-1, straw yield ha-1, number of grains panicle-1, productivity day-1 and productivity plant-1. With regard to grain quality parameters such as 1000 grain weight, milling percentage and head rice recovery, check varieties showed superior performance over hybrids. High variability and heritability was noticed for most of the yield characters. High genetic advance coupled with high heritability were observed for plant height, grain yield ha-1, straw yield ha-1, number of grains panicle-1 and 1000-grain weight. The traits such as days to 50 per cent flowering, plant height, straw yield ha-1, harvest index, number of days to physiological maturity, productivity day-1 and volume expansion ratio can be used for direct selection for yield improvement since they had exhibited significant positive correlation with grain yield. Stability analysis revealed that the hybrid KRH-2, which had recorded highest mean value and regression coefficient less than unity, performed well even under poor management conditions. Therefore KRH-2 can be recommended for general cultivation in central zone of Kerala. For better management conditions, NSD-2 that had responded well to good management, can be recommended. Heterosis studies revealed the presence of significant amount of standard heterosis in most of the hybrids for yield and yield attributing traits. Significant inbreeding depression was also observed for yield and yield attributing characters.
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    ThesisItemOpen Access
    Genetics of trailing habit in yard long bean(Vigna unguiculata var. sesquipedalis(L) Verdcourt)
    (Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2004) Anisha George; KAU; Mareen Abraham
    A study has been undertaken in the Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, to investigate the ‘Genetics of trailing habit in yard long bean (Vigna unguiculata var. sesquipedalis (L.) Verdcourt)’ and to identify the potential parents and superior cross combinations of trailing and bush types cowpea during 2002-04. Two trailing varieties and three bush varieties were used for study. The study revealed that pod yield, length of pod, number of pods per plant, days for first flowering and first harvesting were mainly influenced by allelic contribution where as duration of crop and pod yield can be used as selection parameters of crop improvement. Pod yield can be increased by selecting the genotypes having shorter days for first flowering and harvesting, increased number of pods per plant, lower number of seeds per pod, lower number of branches and higher number of pods. Trailing type, Lola has higher breeding value compared to Vyjayanthi and TC-99-1 and can be exploited for heterotic vigour for many of the yield attributes. The segregants can be used for fixing characters of both bush type coupled with trailing traits. Segregants of Lola x Pusa Komal can give higher pod yield and the yield attributes can be easily fixed in the segregating generations due to its low inbreeding depression. Trailing and bush characters showed a 3:1 monohybrid ratio and stem pigmentation (purplish: green) showed a dihybrid ratio of 9:7 in the F2 segregants of different combinations. Flower colour (purple: white) and pod colour (purple: green) showed a monogenic segregation ratio of 3:1 where as seed coat colour showed dominant epistatic gene action (12:3:1) in various crosses. Segregants can be further screened for higher pod yield coupled with tolerance to biotic and abiotic stresses, which is indicated as future line of work.