High Genotypic Coefficient Of Variation Research Articles

Analysis of genetic variability, heritability and genetic advance for yield and yield associated traits in some promising advanced lines of rice

A field experiment was conducted using twenty three rice genotypes including three check varieties during the period from June to December, 2013, at the Agronomy Field Laboratory, Department of Agronomy, Bangladesh Agricultural University, Mymensingh to study genetic variability, heritability and genetic advance (GA) for yield and yield associated traits in rice. The experiment was laid down in a randomized complete block design with three replications. Plant height, number of filled grains per panicle, days to 50% flowering, thousand grain weight, grain width and grain yield showed relatively high genotypic co-efficient of variation (GCV) and phenotypic co-efficient of variation (PCV) estimates. The PCV were higher than GCV for all eight traits indicating that they all interacted with the environment to some extent. High heritability was obtained for grain width (88.54%), followed by days to 50% flowering (87.61%), thousand grain weight (81.96%), grain length (81.94%), days to maturity (81.81%) and number of filled grains per panicle (78.19%) which indicates high heritable portion of variation. High to medium estimates of heritability and genetic advance were obtained for number of filled grains per panicle (18.97), days to 50% flowering (11.89), days to maturity (12.16) indicating the roles of additive gene action and a good scope of selection using their phenotypic performance. Considering, all of these characters, filled gains per panicle and days to 50% flowering and maturity were important yield related traits and could be used for selection in rice breeding programs.Progressive Agriculture 26:26-31, 2015

Variability for yield, yield related traits and association among traits of sorghum (Sorghum Bicolor (L.) Moench) varieties in Wollo, Ethiopia

Sixteen sorghum varieties were tested in a randomized complete block design with three replications at Sirinka Agricultural Research Center and Kobo sub-center in 2010 with the objectives of estimating the genetic variability, associations among the traits and determining the direct and indirect effect of the traits on grain yield of varieties across the two locations. Analysis of variance revealed that there were statistically significant differences among the varieties for most of the traits across the two locations. From this combined analysis of variance, significant (P=0.01) effect due to location, varieties and GxE was observed for most of the traits. In terms of mean value performance, the varieties showed wider variability in grain yield which ranged from 762.6-2533.3 kg/ha over locations. A relatively high phenotypic coefficient of variation (PCV) values (>20%) were obtained for leaf area index, plant height, panicle weight, panicle yield, grain yield and harvest index across locations. Similarly, high genotypic coefficient of variation (GCV) values (> 20%) were also obtained for leaf area index, plant height, panicle yield, grain yield and harvest index. High heritability estimates (> 80%) were obtained for days to heading, days to flowering, leaf area index, days to maturity, plant height, panicle length and 1000 seed weight. But a relatively high genetic advance was obtained for only leaf area index, plant height, panicle yield, grain yield and harvest index. Grain yield showed significant (P=0.01) positive phenotypic correlations with plant height, panicle weight, panicle yield and harvest index and genotypic correlations with panicle yield. Similarly, significant (P=0.01) positive phenotypic and genotypic correlations between the independent traits was observed. From the path analysis, plant height, panicle weight and harvest index showed high positive phenotypic direct effect on grain yield whereas panicle yield showed negligible positive phenotypic direct effect with considerable indirect effect via panicle weight. At genotypic level, panicle yield showed the highest positive direct effect followed by harvest index and plant height whereas panicle weight showed negative direct effect with high positive indirect effect via panicle yield. Key words: Genotypic variance, genotypic coefficient of variation (GCV), phenotypic coefficient of variation (PCV), heritability, correlation, direct and indirect effect.

English

Twenty two (22) recombinant inbreed lines (RIL’s) derived from interspecific cross derivative of Oryza sativa and Oryza rufipogon along with two local check varieties MTU 7029 and Ranjit were evaluated in randomized block design (RBD) with two replications at two different environments (1 st at Regional Research Station, New Alluvial Zone (NAZ), Bidhan Chandra Krishi Viswavidyalaya, Sub-Centre, Chakdah, Nadia, West Bengal during Kharif season 2009 and 2 nd at Instructional Farm, Bidhan Chandra Krishi Viswavidyalaya, Jaguli, Nadia, during Kharif season 2010), to study the polygenic variations in yield for yield and its attributing characters and their cause and effect relationship. The analysis of variances revealed the significant differences among the 24 genotypes against all the characters except panicle weight, grain length, grain breadth and grain L/B ratio. The magnitude of phenotypic coefficients of variation (PCV) was higher than genotypic coefficients of variation (GCV) for all the characters suggesting the influences of the environmental forces on the expression of these characters. High PCV and GCV values were observed in grain yield per plant, 1000 grain weight, L/B ratio, grain breadth and panicle weight. High heritability coupled with moderate to high genetic advance as percent of mean for plant height, panicle weight, grain length, grain L/B ratio, 1000 grain weight and yield per plant while low heritability estimates along with low genetic advance were observed for fertility percentage and florets number per panicle. In general, genotypic correlation coefficients were higher than their corresponding phenotypic correlation coefficients. Path coefficient analysis revealed that number of characters chosen was very much appropriate as evident from low value of residual effect. Maximum positive direct effect was imparted by number of gains per panicle followed by grain L/B ratio, days to 50% flowering and panicle length respectively. Florets number per panicle imparted the maximum negative direct effect followed by grain breadth, fertility percentage and panicle number per plant. Per se performance revealed that two lines viz; KS-7 and KS-13 were promising in respect of grain yield and some other yield related traits. Number of grains per panicle and floret number per panicle give significant positive correlation with yield. Key words: Correlation, genotypic coefficients of variation, genetic advance, heritability, phenotypic coefficients of variation, rice, recombinant inbreed lines.

English

Tannia is one of the most important root and tuber crops for food, feed and industrial applications worldwide. However, the progress to variety development in Ethiopia is so slow due to lack of adequate germplasm characterization and agronomic evaluation for yield and quality. Therefore, a total of 64 tannia genotypes were studied to determine the extent of genetic variability among genotypes at Jimma agriculture research center during 2013/2014 cropping season. 62 of the genotypes were collected from south, south western and western parts of Ethiopia and the rest two were introduced from Cuba, laid out in 8 × 8 simple lattice design. Analysis of variance revealed significant (P£0.01) differences for most of the characters, indicating the existence of variability among the studied genotypes. High phenotypic coefficient of variation (PCV) along with moderate to high genotypic coefficient of variation (GCV) as well as high heritability coupled with high genetic advance as percent of the mean were obtained for number of suckers per plant, number of cormel per plant, total yield per plant, corm and cormel fresh weight per plant. This indicates that there is an opportunity and potential for further utilization of its genetic improvement through selection and hybridization. However, the presence of morphological variation between genotypes is not a guarantee for high genetic variation. Hence, there is a need to confirm genotype-environment interactions and use biotechnological approaches as a complementary to this study. Key words: Genetic advance, genetic variability, genotypic coefficient of variation, heritability.

Estimates of genetic traits in silkworm (Bombyx moriL.) Under temperate conditions of Kashmir

The genetic parameters, trait association and path coefficient analysis between silkgland weight and its attributes of 10 silkworm genotypes were studied during spring and summer seasons of 2010–11 at TSRI, SKUAST-Kashmir (Mirgund). The genotypes exhibited wide range variability for all the traits studied. High heritability accompanied by moderate to high genotypic coefficient of variation and genetic gain were observed for filament length, shell ratio, single shell weight and filament size. Correlation studies indicated that during spring season, silkgland weight showed positive and significant correlation with shell ratio, while it showed significantly negative association with silkgland somatic index, while during summer season it showed significant positive association with all the traits except silk conversion index. The silkgland attributes exhibited varied magnitude of direct effects on silkgland weight during both spring and summer season. During summer season single shell weight showed the highest direct positive effect on silkgland weight which was followed by the filament length, while during spring season, highest positive direct effect on silkgland weight was exhibited by cocoon shell percentage(3.574) and single shell weight (3.346).

Variability and character association studies in dolichos bean (Lablab purpureusL.) genotypes

The present investigation was carried out at Horticultural College and Research Institute, Venkataramannagudem, West Godavari Dist. (Andhra Pradesh). The experimental material comprised of 12 genotypes of Lablab purpureus collected from IIPR Kanpur and AICRP on pigeon pea Bangalore. A wide range of variability was reported in most of the characters. The highest genotypic coefficient of variation was recorded for number of pods per plant followed by pod yield per hectare and lowest in days to first pod harvest. Higher heritability estimates coupled with high genetic advance as per cent of mean were observed for all the characters except days to first harvest and pod width. Correlation coefficient analysis revealed that number of secondary branches per plant, number of inflorescences per plant, number of pods per inflorescence, number of pods per plant, number of seeds per pod, pod width, days to last harvest and 100 seed weight had the significant positive correlation with marketable green pod yield per plant. Path analysis revealed true relationship between yield and number of secondary branches per plant, number of pods per inflorescence and number of pods per plant and direct selection for these traits will be rewarding for yield improvement as correlation was due to direct effect of the characters. Hence, selection based on these characters could be effective in developing high yielding varieties of dolichos bean for coastal Andhra Pradesh.

Genetic Variability for Quantitative Traits in China Aster [Callistephus chinensis (L.) Nees

A field study was conducted to estimate genetic variability, heritability and genetic advance in 20 genotypes of China aster for 15 traits during the year 2012-13 in Randomized Complete Block Design, with three replications. Results revealed that the magnitude of phenotypic co-efficient of variation (PCV) was higher than genotypic co-efficient of variation (GCV) for all the traits studied. Narrow differences between GCV and PCV were recorded in all the characters except flowering duration, vase-life and shelf-life, indicating little environmental influence on expression of these characters. High (>20%) GCV and PCV were recorded for plant height, number of branches and leaves per plant, flower diameter, number of ray and disc florets/flower head, stalk length, and, number and weight of flowers/plant. Heritability estimates ranged from 28.30% (flowering duration) to 99.54% (flower diameter). High heritability (<60%) was observed for all the traits except flowering duration. High heritability, coupled with high genetic advance as per cent mean, was recorded for flower diameter, stalk-length, number of branches/plant, weight of flowers/plant, days to first flower opening, days to 50 per cent flowering, plant height, number of leaves/plant, number of ray and disc florets/flower head, number of flowers/plant, indicating a possible role of additive gene action. Thus, these traits can be improved through selection and breeding.

Variability and heritability analysis in F4 genotypes of Brassica rapa L.

A field experiment was conducted in the experimental field of Genetics and Plant Breeding Department, Sher-e Bangla Agricultural University, Dhaka, Bangladesh to study variability in 10 F4 lines obtained through intervarietal crosses along with 8 released varieties of Brassica rapa. Significant variation was observed among all the genotypes for all the characters studied. Considering genetic parameters high genotypic co-efficient of variation (GCV) was observed for number of secondary branches per plant, siliquae per plant, yield per plant, whereas days to maturity showed very low GCV. High heritability with low genetic advance in percent of mean was observed for days to maturity which indicated that non-additive gene effects were involved for the expression of this character and selection for such trait might not be rewarding. High heritability with moderate genetic advance in percent of mean was observed for plant height and days to 50% flowering indicating that this trait was under additive gene control and selection for genetic improvement for this trait would be effective. Considering, inter genotypic variability, heritability, and genetic advance, % coefficient of variation and other agronomic performance G2, G14, G18, G1, G9, G12, G16, G17 may be considered to be better parents for future uses in hybridization programme. DOI: http://dx.doi.org/10.3329/bjar.v39i2.20426 Bangladesh J. Agril. Res. 39(2): 227-241, June 2014

Seed and Seedling Vigour in Tropical Maize Inbred Lines

Abstract Seed and seedling vigour is an aspect of seed quality which affects field establishment and performance. Low maize yields have been reported to be affected by several factors in which poor quality seed with low seed and seedling vigour. Information is scarce on seed and seedling vigour in maize inbred lines developed for tropical environments. Fifteen genotypes of tropical maize (Zea mays L.) inbred lines were evaluated to determine the level of differences in seed and seedling vigour traits, and extent of relationships among traits and their heritability. A substantial amount of genetic variability was found, which suggested that most of the traits under study could be improved through selection and utilized in breeding programs. Positive and significant interrelationship among seed germination and seedling traits and a positive correlation between seed germination and seed vigour and field emergence showed that these could be given due consideration in crop improvement for seed and seedling vigour. High genotypic coefficient of variation, heritability and genetic advance were obtained for seed germination, seed emergence, shoot length and seedling vigour index I and II, revealing the possibility of improvement in these characters through direct selection. The principal component analysis (PCA) identified seed emergence, shoot length, seedling vigour index I and II and tetrazolium vigour as characters that contributed greatly to variation in seed vigour in the maize inbred lines. Cluster analysis partitioned the genotypes into two groups, with group I consisting of seven genotypes and group II comprised the other eight genotypes, which suggested that hybridization between the two groups could lead to high level of heterosis. Genotype V5 had superior seedling vigour traits compared to other genotypes. Seedling emergence, shoot length, seedling vigour index I, seedling vigour index II and tetrazolium vigour are effective characters for good seedling vigour traits in maize inbred lines investigated.

Genetic Analysis in Segregating Generation of Wax Gourd

Wax gourd, commonly called ash gourd in India [Benincasa hispida (Thunb.) Cogn.], has a long storage life and value can be added after processing. Though there is variation in wax gourd traits, especially fruit characters, little work has been done related to genotype variability. The F2 progenies of the crosses ‘Indhu’ בCO-2’ (cross 1), ‘Indhu’ בVasundhara’ (cross 2), and ‘Vasundhara’ בKAU Local’ (cross 3) and selfed parents were studied. Observations on 15 characters were recorded on single plants in each F2 segregants of crosses for genetic analysis. Cross 2 had the highest fruit yield per plant with the most branches, highest number of female flowers, most fruit, highest fruit weight, greatest fruit diameter, thickest flesh, and highest percentage sex ratio, followed by cross 1. High genotypic coefficient of variation (GCV) and high heritability and genetic advance occurred in the F2 segregating population of cross 2 for yield per plant, flesh thickness, fruit length, fruit diameter, fruit weight, number of fruit, and sex ratio, indicating that these traits were governed by additive genes. These characters can be used as criteria for selecting plants in the segregating population. From correlation and path analysis, earliness in flower opening, sex ratio, number of fruit, individual fruit weight, and flesh thickness had significant, positive correlations and high direct, positive effects on yield. These characters can be used as selection indices for further improvement through breeding. Frequency distribution of F2 progenies exhibited a transgressive pattern on a wider range in a positive, unidirectional distribution at high proportion over parental values for yield and most characters in cross 1 and cross 2. For these populations simple pure line selection could be used to improve fruit yield per plant.

Studies of variability and association of yield with some agromophological characters in bread wheat (Triticum aestivumL.)

The experiment was conducted to study the variability parameters, correlations and path coefficient for ten agronomically important traits in the 40 bread wheat genotypes. Genotypic coefficient of variation (GCV) was less as compared to that of phenotypic coefficient of variation (PCV) for all the characters. Plant height and grain weight per plant had high GCV, heritability and genetic advance (as percentage of mean). This indicated that these characters were governed by additive gene effect and can be improved through selection effectively. Highly positive and significant correlation reported for grain yield per plant with number of tiller per plant, number of spikelets per spike, 100-grain weight and grain weight of main spike. The present study indicated that number of tillers per plant had highest direct effect on seed yield per plant both at genotypic levels and grain weight of main spike.

Character association and path analysis in hip rose (Rosa sp.) genotypes collected from North Western Himalayan region of Kashmir

Thirty six genotypes of hip rose (Rosa sp.) collected from different areas of Kashmir valley and studied for nine polygenic characters. These revealed higher PCV than corresponding genotypic coefficient of variation (GCV) for plant height, fruit yield, fruit weight, fruit diameter, fruit length, pulp content, pulp to seed ratio, TSS and number of seeds. High heritability accompanied by moderate to high genetic gain and GCV were observed for plant height and yield which could be improved by selection in early generations. Fruit diameter (74.2%), fruit length (80.4%), fruit weight (79.9%) exhibited high heritability coupled with moderate GCV and low genetic gain which needs selection over several successive generations following hybridization for their edification. Genotypic correlations were of higher magnitude to the corresponding phenotypic ones, thereby establishing strong inherent relationship among the characters studied. The phenotypic and genotypic associations of fruit diameter was significantly positive with fruit weight (r = 0.337, 0.418), fruit pulp weight (r = 0.429, 0.507), number of seeds per fruit (r = 0.259, 0.0.406) and plant height (r = 384, 0.417). However, fruit length were significantly linked with fruit weight, pulp weight and fruit flesh ratio. Overall path analysis indicated that highest positive direct effect was showed by average fruit weight (6.694) followed by fruit flesh ratio (3.103), number of seeds per fruit (1.201), plant height (0.993), and fruit length (0.426); however, fruit diameter (-0.327), pulp weight (-8.319) and TSS (-0.529) showed negative direct effects on total hips yield which should be considered simultaneously for amenability in rose hips yield in Rosa species. Key words: Character association, Rosa sp., path analysis, North Western Himalayan, Kashmir.

GENETIC VARIABILITY, CORRELATION AND PATH COEFFICIENT ANALYSIS OF YIELD AND QUALITY TRAITS IN PUMPKIN (Cucurbita moschata Duch ex Poir.)

The experiment was conducted to study variability, correlation coefficient and path analysis for yield and quality related traits of 30 pumpkin genotypes. Significant variations were found among the genotypes for most of the characters studied. High genotypic coefficient of variation (GCV) and high heritability coupled with high genetic advance in percent of mean were observed for beta-carotene followed by non-reducing sugar, number of seeds per fruit, yield per plant, dry weight, flesh thickness, number of male flowers per plant and number of female flowers per plant which indicated that these characters were under additive gene control and selection for genetic improvement for these traits might be effective. Correlation co-efficient between yield per plant with number of primary branches, number of fruits per plant and single fruit weight were positive and highly significant. On the other hand, days to first female flower, number of male flowers per plant, ß- carotene and total sugar showed positive and insignificant correlation with yield per plant. But correlation between brix content and yield per plant were significantly negative. Path coefficient analysis revealed that the maximum direct contribution towards yield was obtained through number of fruits per plant followed by days to first female flower and single fruit weight indicated that these traits should be considered as primary components of yield. Negative direct effect on yield was exerted by total sugar followed by number of female flowers per plant, reducing sugar and brix content. Considering all the qualitative and quantitative traits ten genotypes as G7, G13, G14, G17, G18, G19, G20, G22, G27, G29 among thirty were selected and suggested to be selfed for the development of inbred line for use in future breeding programme.DOI: http://dx.doi.org/10.3329/bjpbg.v26i1.19981

Studies on Genetic Variability in Gerbera (Gerbera jamesonii Bolus Ex. Hooker F.)

Thirteen genotypes of gerbera were evaluated under naturally-ventilated polyhouse in Completely Randomized Block Design during the year 2011-12 to determine genetic variability, heritability and genetic advance for 15 quantitative traits, based on which selection may be made. Analysis of Variance showed significant differences among genotypes for all the characters studied. Results revealed that magnitude of the Phenotypic Coefficient of Variation (PCV) was higher than Genotypic Coefficient of Variation (GCV) for all the traits, indicating greater genotype and environment interaction. High (>20%) PCV and GCV was observed for number of leaves/plant and leaf width. Heritability estimates ranged from 24.03% (number of suckers/plant/year) to 93.5% (length of ray floret). High heritability (>60%) was observed for all traits except number of suckers/plant/year, flower diameter and flower-stalk diameter. High heritability, coupled with high genetic advance over per cent of mean, was observed for number of leaves/plant, leaf length, leaf width, days to bud-burst, days to first-flower opening, disc diameter, flower-stalk length, number of ray florets per flower head with length and width of ray florets.

English

The present investigation was carried out with the objective to find out the extent of genetic variation, heritability and genetic advance for 13 characters in 34 exotic genotypes of Italian millet during Autumn 2008 and Spring 2009. High phenotypic coefficients of variation (PCV) coupled with high genotypic coefficients of variation (GCV) were observed for grain yield per plant, ear weight, calcium content and carotene during both seasons. The trait 1000 grain weight recorded high PCV and GCV during Autumn, whereas number of productive tillers per plant and straw weight during Spring. Straw weight showed high GCV during Autumn. It indicated presence of wider variability for these traits in the genotypes studied. High heritability coupled with high genetic advance as percent of mean recorded for all characters except days to 50% flowering, days to maturity and plant height during both seasons reveals operation of additive gene action in the inheritance of these traits and improvement in these characters is possible through simple selection. Key words: Italian millet, gene action, Seteria, foxtail millet.

Inheritance and Association of Quantitative Characteristics in Syrian Landraces of Garden peas (Pisum sativumL.)

In a study conducted at Dara'a Center of Scientific Agricultural Research, GCSAR, Syria, during two growing seasons 2010–2011 and 2011–2012, 13 pea genotypes were grown in a randomised complete block design with three replications. This investigation aimed to find out the nature and magnitude of genetic variability, correlation and path coefficient of different characteristics. Analysis of variance revealed highly significant differences among genotypes for days to 50% flowering, days to marketable maturity, internode length (cm), pod length (cm), pod width (cm), filling degree, shelling percentage (%), ten-green pod weight (g), biological yield per plant (g), harvest index (%) and pod yield per plant (g). ten-green pod weight, biological yield per plant and pod yield per plant showed high genotypic coefficient of variation accompanied with high heritability and genetic advance as percent of mean indicating good scope for selection. The correlation studies indicated that, in general, estimates of genotypic correlation coefficient were higher than corresponding phenotypic correlation coefficient. Significant and positive associations were observed between pod yield per plant and 10-green pod weight, biological yield per plant and harvest index, suggesting that these characteristics could be considered as major green pod yield contributing characteristics in garden peas. Path coefficient analysis revealed that days to marketable maturity, biological yield per plant and harvest index exhibited the maximum positive direct effect on pod yield per plant indicating the importance of these three attributes while making selection of high yielding genotypes in garden peas.

Genetic and Correlation Studies in Double Genotypes of Tuberose (Polianthes tuberosa) for Assessing the Genetic Variability

Five genotypes of tuberose (double) were evaluated for twelve different parameters to ascertain the genetic variability and association among the characters during the year 2011-12 at Tamil Nadu Agricultural University, Coimbatore. The results of the experiment revealed that ‘Suvasini’ showed its superiority for certain parameters viz., plant height, number of leaves per plant, number of florets/ spike, length of the floret, weight of florets per spike, number of spikes/m2 and yield of florets/ plot (2×2 m). The phenotypic coefficient of variation (PCV) was higher than genotypic coefficient of variation (GCV) for all twelve characters studied. The higher PCV and GCV estimates were found for number of florets/spike. High heritability with high genetic advance was observed for number of florets per spike, number of spikes/m2, rachis length and yield of florets per plot (2×2 m). The correlation studies revealed that plant height exhibited positive correlation with spike length, yield of florets/plot (2×2 m), number of florets per spike, flowering duration, number of leaves per plant, weight of florets per spike, number of spikes/m2, rachis length and length of the floret. There exists a positive relationship of number of leaves per plant with weight of florets per spike, yield of florets/plot (2×2 m), spike length, flowering duration, and number of florets per spike, length of the floret, number of spikes/m2 and rachis length. Spike length exhibited positive and significant association with yield of florets/ plot (2×2 m), number of florets per spike, weight of florets per spike, number of spikes per m2, length of the floret and rachis length.

English

The present investigation was planned and executed during spring and summer seasons of 2007 to 2010 at Vegetable Experimental Farm, Faculty of Agriculture, Sher-e-Kashmir University of Agricultural Sciences and Technology, Main Campus, Chatha. The experimental material include 60 diverse genotypes of tomato collected from various places including Indian Institute of Vegetable Research Institute (IIVR) Varanasi Uttar Pradesh and some local cultivars. The observations were recorded on yield and quality traits to generate information regarding the extent of genetic variability, heritability and expected genetic advance. Analysis of coefficient of variation revealed that the magnitude of the phenotypic coefficient of variation was higher than that of the genotypic coefficient of variation for all the seven characters under study. The highest values of the phenotypic coefficient of variation (PCV) were recorded for fruit yield, number of locules per fruit and pericarp thickness. High genotypic coefficients of variation (GCV) were recorded for yield polygalacturonase activity and pericarp thickness. High heritability was recorded for most of the characters, namely, pericarp thickness, polygalacturonase activity and alcohol insoluble solids. The above results are quite encouraging for advancing in tomato breeding. Key words: Germplasm evaluation, tomato, genotypes.

English

There is continuing need to identify traits that can facilitate selection of productive progenies. For this, 18 genotypes of okra [Abelmoschus esculentus (L.) Moench] were evaluated for the extent of genetic variability, heritability, correlation and path analysis among various morphological, reproductive and nutritional characters related to fruit yield over two growing seasons in the Gangetic plains of eastern India.Phenotypic co-efficient of variation (PCV) agreed closely with the genotypic co-efficient of variation (GCV) but the magnitude of PCV was higher than GCV for almost all the characters studied during both seasons which reflect the influence of environment on the expression of traits. High PCV and GCV values were shown by fruit yield per plant, numbers of fruit per plant and plant height at flowering during both seasons. The remaining traits recorded moderate to low PCV and GCV estimates, indicating that selection for these characters will be less effective. All characters studied exhibited moderate to high heritability. However, pooled genetic advance (GA) expressed as percentage of mean was high for fruit yield per plant, numbers of fruit per plant, plant height at flowering and fruit weight. Characters showing moderate to high genetic gain also showed high heritability, indicating that most genetic variations in these characters were due to additive gene effects. From  the correlation and path coefficient analyses, it revealed that the top priority should be given to selection based on numbers of fruit per plant and fruit weight for yield improvement and could be considered while formulating selection indices in the improvement of okra. Key words: Okra, genetic variability, heritability, correlation, path analysis  

Studies on genetic variability for morphological, water use efficiency, yield and yield traits in early segregating generation of groundnut (Arachis hypogaea L)

Twenty eight F2 populations were evaluated for genetic parameters of 23 characters of morphological, physiological, yield and yield attributes during spring 2009. TPT-4 x ICGV-91114 was distinct for its lowest mean value for days to maturity and highest mean values for number of well-filled and mature pods per plant, shelling percentage, 100- kernel weight. The F2 involving JL-220 as one of the parentsviz., JL-220 x ICGV-99029 for SCMR, JL-220 x TCGS-647 for SMK percentage, protein percentage, kernel yield per plant and pod yield per plant showed the highest per se performance. High genotypic coefficient of variation was observed for the number of secondary branches per plant. High heritability and high GAM was recorded for the number of secondary branches per plant, high heritability and moderate GAM were observed for days to 50% flowering. The leaf area index, number of well-filled and mature pods per plant, dry haulms yield per plant and harvest index showed moderate heritability and high GAM. This indicates that these characters are under additive genetic control and selection for genetic improvement will be worthwhile and may rapidly contribute to pod-and kernel yields. Key words: Groundnut, genetic variability, heritability, genetic advance and genetic advance as percentage of mean.