1 Background

Chickpea (Cicer arietinum L.) also called Bengal gram or Garbanzo, is an annual grain legume and ranks second after pigeon pea. It is widely used in human diet and good source of protein, energy, fibre, vitamins [Tryptophan and lysine (Awasthi et al., 1991; Hulse, 1991)] and minerals. It is also a rich source of calcium and phosphorus as compare to other than pulses (Singh et al., 2000) and low amount of anti-nutritional factors like tannins, alkaloids or enzyme inhibitors (Williams and Singh, 1987). During 2012-13, the total pulse production in India was 18.34MT which further increased by another 7.85% in 2013-14 with a production of 19.78 MT, touching an all time high record. Among the pulse production, 48% of production is contributed by chickpea. During 2013-14, the major pulse growing states in India are Karnataka, Maharashtra and Rajsthan. Among the different pulses, the highest growth rate was observed in chickpea production (5.89%) followed by pigeonpea (2.61%).

The extent of genetic variation is a pre-requisite in any crop improvement and yield is an end product of many field crops (Singh et al., 1995). Some of the characters are highly associated among themselves and with seed yield. The analysis of the relationships among these characters and their associations with seed yield is essential to establish selection criteria. However, simple correlation coefficients between seed yield and yield components may not give satisfactory results. Because, the components do not only directly affect the yield, they also affect the yield indirectly by affecting other yield components in negative or positive manner. As a trait has helpful effect on a trait for seed yield, it can affect some other or all traits negatively (Walton, 1980). Under such situations, the path coefficient analysis helps to determine the direct contribution of these characters and their indirect contributions via other characters (Singh et al., 1990). For this reason, many of the studies on correlation and path analyses have been conducted in chickpea crop. The present investigation was carried out to understand the nature of gene actions and type of association among characters and the extent and nature of direct and indirect effects of component traits on seed yield/plant in desi chickpea varieties.

2 Results and Discussion

The combined analysis of variance (Table 1) revealed significant differences among the genotypes and environments for all the traits suggesting the presence of variability both among genotypes and environments. The mean squares due to G x E interaction were significant for all the traits. Significant mean squares due to environment (linear) indicated considerable differences among environments and their predominant effects on all the traits (Table 1). Pooled deviation was significant for all the traits except number of primary branches/plant and seeds/pod indicating the importance of non-linear components in the manifestations of G x E interaction of these significant traits. Similar results were also reported by Alwawi et al., (2009).

Table 1 Analysis of variance for yield and its contributing traits in combine over environments in Chickpea

Variability

Broad sense heritability estimate does not serve as a true indicator of genetic potentiality of genotypes. It is advisable to consider the predicted genetic advance along with heritability estimates as tool in selection programme. High heritability along with high genetic advance were observed for traits viz., number of pods/plant, pod length  and 100 seed weight (Table 2) indicated that these traits are governed by additive-gene action and continued selection in subsequent generations will be highly responsive. The increase in heritability is an indication of effective selection and more useful when coupled with high genetic advance. Similar results were also reported by Chavan et al., (1994) and Malik et al., (2010).

High heritability along with moderate genetic advance was observed for plant height and seed yield/plant, thus showed the presence of non-additive gene action. The high heritability is being exhibited due to favorable influence of environment rather than genotype and selection for such traits may not be rewarding. High heritability accompanied with low genetic advance was observed for number of primary branches/plant, number of secondary branches/plant, number of seeds/pod, days to 50% flowering and days to maturity indicated the presence on non-additive gene action.

Table 2 Genetic parameters for yield and yield contributing traits in combined over environments in chickpea

Correlation coefficient analysis

The analysis of variance showed that the genotypes differ significantly among themselves for all the characters studied indicating the presence of sufficient variability in the material. Genotypic correlations were, in general, higher in magnitude than corresponding phenotypic correlations coefficients. At phenotypic level positive and highly significant correlation of seed yield per plant found with number of seeds per pod (0.77), pod length (0.68),  plant height (0.59), days to maturity (0.54), number of pods/plant (0.49) and 100 seed weight (0.49) (Table 3). These results are in agreement with the earlier findings in chickpea (Chand et al., 1997; Ali et al., 2010).  The seed yield/plant is a result of interaction between component characters, which are either positively or negatively correlated with each other. Pod length had highly significant and positive correlation with number of seeds/pod (0.52), 100 seed weight (0.62) and seed yield/plant (0.68). The association of number of pods per plant was also highly significant and positive with plant height, number of primary branches/plant, number of secondary branches/plant and seeds/plant. Arshad et al., (2003) reported high genetic correlation than phenotypic correlations in chickpea.100 seed weight recorded significant positive correlation with pod length, seed yield/plant and negative with number of primary branches/plant. Similar results were also reported by Vivek et al., (1999).

Table 3 Estimates of correlation coefficients at genotypic level/phenotypic among different traits studied in combined over environments in chickpea

Path coefficient analysis

The estimates of direct, indirect and total effects of seed yield components on seed yield/plant are presented in (Table 4). The plant height had the largest direct effect on seed yield/plant (0.46) followed by number of primary branches/plant (0.30), days to maturity (0.23), number of seeds/pod (0.21), 100 seed weight (0.19) and pod length (-0.05) exhibited negative direct effect on seed yield/plant. The seed yield/plant manifested positive correlation with 100 seed weight but path analysis showed negative direct effect with seed yield/plant. The positive correlation was because of indirect effects via plant height, number of pods/plant and days to 50% flowering. The number of pods/plant had positive correlation with seed yield/plant but path analysis showed that it’s positive indirect effects via plant height, number of primary branched/plant, number of seeds/pod and 100 seed weight.

The present study suggests that selection for high seed yield should be based on traits such as number of pods/plant, 100 seed weight, plant height, days to maturity, pod length, days to 50% flowering and number of seeds/pod in chickpea.

Table 4 Estimates of direct and indirect effects at genotypic (P)/phenotypic level for different characters studied in combined over Environment in Chickpea on seed yield/plant

3 Materials and Methods

The experiments were conducted at the experimental farm of Krishi Vigyan Kendra, Poonch of Sher-e- Kashmir University of Agricultural Sciences & Technology (SKUAST)-Jammu during rabi 2009-10, 2010-11 and 2011-12 continuously for three years under rainfed conditions. The material for present study consisted of seventeen varieties of chickpea (81-0-800, 96907, 90201, C-81, 96910, C-306, C-235, C-294, GNG-469, SCS-3, PBG1, 88-2, 95909, HPG17, 96911, 96904 and C17) with wider adaptability in areas of their recommendation. In all the three years, the experiments were laid out in Randomized Block Design (RBD) with three replications, the rows being 2.5m long at 30cm between rows and 15 cm between plants. The data was recorded on ten randomly selected plants using standard procedures for number of primary branches/plant, number of secondary branches/plant, plant height (cm), days to 50 % flowering, days to maturity, seed yield/plant (g), number of seeds/pod and 100-seed weight (g). The recommended package and practices was followed to raise a good healthy crop. The pooled mean values of all the characters for the three years were used for detailed statistical analysis. The data were subjected to statistical analysis of variance as per the procedure suggested by Sukhatme and Amble (1989). The heritability and genetic advance as per cent of mean was worked out as per the method of Hanson et al., (1956) and Robinson et al., (1949), respectively. The correlation coefficients for all the characters combinations were computed according to Al-Jibouri et al., (1958). The correlation coefficient was partitioned into components of direct and indirect effects by path coefficient analysis as suggested by Dewey and Lu (1959).

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