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P. SYAMALA*, N.V. NAIDU, C.V. SAMEER KUMAR, D. MOHAN REDDY AND B. RAVINDHRA REDDY
Department of Genetics and Plant Breeding, S.V. Agricultural College, ANGRAU, Tirupati-517 502, Chittoor Dt., A.P.
The present investigation comprising of nine parents and 20 cross combinations of pigeonpea (Cajanus cajan (L.) Millsp.) developed through Line X Tester (5 × 4) crossing programme were evaluated for genetic parameters. High GCV and PCV, heritability and genetic advance as per cent mean were observed for the characters viz., secondary branches per plant, pods per plant, harvest index and seed yield per plant both in parents and crosses, indicating these characters are under the control of additive genetic variance.
Pigeonpea, variability, genetic advance and heritability.
Pigeonpea (Cajanus cajan (L.) Millsp.) is an important leguminous short lived perennial cultivated as annual crop in semi-arid tropical and subtropical regions of the world. It is generally cultivated as a sole crop or as a inter crop with short duration cereals or legumes as well as with other crops such as cotton and groundnut. Across the globe, pigeon pea is cultivated in 6.22 m ha-1, with an annual production of 4.74 m tons and productivity of 762 kg ha-1.
India is the leading producer of pigeonpea in the world accounting for 3.89 m ha-1 area, 2.78 m tons of production and productivity of 727 kg ha-1 (FAO, 2016). Fallen leaves from the plant provide vital nutrient to the succedding crop and also enriches soil through symbiotic nitrogen fixation (Varsheny et al., 2010). India is the world largest pigeonpea producer accounting for 90 per cent of the world production. New hybrids varieties have to be developed to attain high yield potential. For this, basic information on genetic variability and inheritance of yield and its component traits are essential to determine the most efficient breeding approaches.
The experiment was carried out in Randomized Block Design with three replications during kharif, 2016 with five lines viz., ICPB-2078, ICPB-2043, ICPB-2047,
ICPB-2048 and ICPB-2092, four testers viz., ICPL-87119, ICPL- 20108, ICPL-20116 and ICPL-20123 and their 20 F1s of pigeonpea obtained by L x T mating design along with a standard check (Maruthi) at ICRISAT, Hyderabad, Telangana. Five plants in each plot in each replications were randomly selected to record the observations for quantitative traits viz., days to 50 per cent flowering, days to 75 per cent maturity, plant height, primary branches per plant, secondary branches per plant, pods per plant, seeds per pod, hundred seed weight, harvest index, seed protein and seed yield per plant. Two characters viz., days to 50 per cent flowering and days to 75 per cent maturity were computed on plot basis. The mean over replication of each character was subjected to statistical analysis. The phenotypic, genotypic coefficient of variation (PCV, GCV), heritability in broad sense and expected genetic advance at 5 per cent selection intensity were computed by using formulae suggested by Siva Subramanian and Menon (1973) and Johnson et al. (1955).
PCV and GCV values were high for secondary branches per plant, pods per plant, harvest index and seed yield per plant both in parents and crosses. Moderate value of PCV and GCV was observed for secondary branches per plant both in parents and crosses. The proportion of genotypic variance was high indicating the variation observed is less influenced by environment and more due to genetic variation. Similar results were observed by
Vange and Moses (2009); Kalaimagal et al. (2008) and Gohil (2006).
The estimates of genotypic coefficient of variation reflect the total amount of genotypic variation present in the material studied. However, the proportion of the genotypic variation, which is transmitted from parents to the progeny, reflected by heritability. Burton (1952) suggested that the genetic variation along with heritability estimates would give a better idea about the expected efficiency of selection. Thus characters possessing high GCV along with the high heritability are valuable in selection programme. In the present study highest heritability in broad sense with high GCV was recorded for number of secondary branches per plant, pods per plant, harvest index and seed yield per plant both in parents and crosses.
High heritability (more than 60%) was observed for all the characters except hundred seed weight and seed protein both in parents and crosses (Table 2). Similar results have been reported by Patel et al. (1998); Bhadru (2008) and Pansuriya et al. (1998) for pods per plant, seed yield per plant, primary branches per plant, plant height and days to 50 per cent flowering. Genetic advance is the improvement in the mean of selected families over
the base population (Lush (1949) and Johnson et al., 1955). It is also expressed as the shift in gene frequency towards the superior side on exercising selection pressure. Genetic advance when expressed as percentage over mean is called genetic gain. Johnson et al. (1955) suggested that heritability and genetic advance when calculated together would prove more useful result predicting the resultant effect of selection an phenotypic expression. Without genetic advance, the estimates of heritability alone will not be of practical value and emphasized the concurrent use of genetic advance along with heritability.
High heritability in conjunction with high genetic advance as per cent of mean was observed for seed yield per plant, pods per plant, secondary branches per plant, primary branches per plant and harvest index both in parents and crosses (Table 2) which indicates the preponderance of additive gene action governing the inheritance of this character and offers the best possibility of improvement through simple selection procedures. These results are in accordance with the findings of Satish Kumar et al. (2005) and Vange and Moses (2009).
