Triallel analysis of yield and resistance to anthracnose in chilli ( Capsicum annuum L)
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Date
2007
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Department of Plant Breeding and Genetics, College of Agriculture, Vellayani
Abstract
. Chilli (Capsicum annuum L.) is an important spice cum vegetable crop grown commercially in India. It is an important constituent of many foods since it adds flavour, colour, vitamin C and pungency. Productivity of the crop remains low mostly due to destructive diseases, of which the most dreaded disease affecting chilli is anthracnose also known as dieback and fruit rot. The best method to tackle the disease is to grow resistant varieties and hence it is essential to breed high yielding anthracnose resistance varieties of chilli. Therefore an investigation was carried out at the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani to estimate the combining ability and heterosis through diallel pattern and combining ability analysis through general line effect of the first kind ((hi), general line effect of the second kind (gi), two line specific effect of the first kind (dij), two line specific effect of the second kind (sij/sji), three line specific effect (tijk), estimates of genetic components and heterosis by triallel analysis to assess the inheritance pattern of anthracnose resistance, yield and yield component traits, identify the order in which the parents should be combined to obtain maximum effect for a particular character and also to formulate an appropriate breeding programme for improving each trait. Six parents viz., Jwalamukhi (P1), Jwalasakhi (P2), Samkranthi local (P3), Vellayani Athulya (P4), Kidangoor local (P5) and Ujwala (P6) along with their 15 F1 hybrids, and their possible three way cross hybrids was evaluated during 2005-2007. Diallel analysis revealed that the magnitude of gca variance was higher than sca variance suggesting the predominance of additive gene action except for number of seeds per fruit, harvest index and vitamin C. On the basis of per se performance of the parents for different traits, P4 was superior with regard to average fruit weight, fruit length, fruit girth and hundred seed weight while P1 for fruit yield per plant and vitamin C. P6 showed high resistance to anthracnose with high enzymatic activity for anthracnose, phenol, peroxidase, polyphenol oxidase, phenylalanine ammonia lyase along with high capsaicin and oleoresin. The hybrid P1xP6 had highest per se performance for fruit yield per plant and number of fruits per plant, P2xP4 for fruit length, average fruit weight, fruit girth, number of seeds per fruit and hundred seed weight and P5xP6 for duration, incidence of anthracnose, disease intensity, biochemical characters, capsaicin and oleoresin. High values of gca effects were noticed for fruit yield per plant, number of fruits per plant and incidence of anthracnose at 45 DAT and 60 DAT. Highest sca effect was recorded for fruit yield per plant, number of fruits per plant and vitamin C. With respect to mean and general combining ability, P2 was superior for days to first flowering, average fruit weight, fruit girth, fruit yield per plant, hundred seed weight and harvest index while P6 for incidence of anthracnose, disease intensity and all the biochemical characters including capsaicin and oleoresin. Among the fifteen hybrids evaluated with respect to per se, standard heterosis and sca effects, P1xP6 was superior with regard to number of fruits per plant, fruit yield per plant, incidence of anthracnose, disease intensity, phenol, peroxidase, polyphenol oxidase, phenylalanine ammonia lyase, capsaicin and oleoresin. In triallel analysis, P4xP6xP1 had highest per se performance for fruit yield per plant, P1xP5xP4 for average fruit weight, fruit length, number of seeds per fruit while P5xP6xP4 had significant per se performance for incidence of anthracnose and high enzyme activity. P6 had the highest general line effect of the first kind (hi) for fruit yield per plant and number of fruits per plant while P1 for days to first flowering, plant height, average fruit weight, fruit length, fruit girth, harvest index and vitamin C. P4 had highest general line effect of the first kind for incidence of anthracnose, disease intensity and for all the enzyme activity. The general line effect of the second kind (gi) was highest in P1 for fruit yield per plant, number of fruits per plant, fruit girth, hundred seed weight and oleoresin while P5 for low incidence of anthracnose, disease intensity and high activity of the enzymes. P6 had highest effect for number of branches per plant, capsaicin, and vitamin C. The two line specific effect of the first kind (dij) was highest in P4xP5 for number of fruits per plant, fruit yield per plant and duration while P1xP6 for incidence of anthracnose, disease intensity and all the enzyme activities. P1 x P2 had highest two line specific effect of the second kind (sij) for fruit yield per plant and number of fruits per plant whereas P4xP6 for incidence of anthracnose, disease intensity, phenol, peroxidase, phenylalanine ammonia lyase and polyphenol oxidase. The two line specific effect of the second kind (sji) reciprocal effect was highest in P5xP4 for fruit yield per plant and average fruit weight while P2xP1 for incidence of anthracnose, disease intensity, phenol, polyphenol oxidase and phenylalanine ammonia lyase. P1xP2xP3 recorded high value of three line specific effect for fruit yield per plant and average fruit weight and P5xP6xP4 for incidence of anthracnose at 60 DAT, phenol, and polyphenol oxidase and phenylalanine ammonia lyase. The hybrid P4xP6xP1 had high relative heterosis and heterobeltiosis for fruit yield per plant. Among the biometrical traits, the relative heterosis was high for fruit yield per plant followed by harvest index and number of fruits per plant whereas heterobeltiosis had maximum per cent for harvest index followed by number of fruits per plant and fruit yield per plant. At 45 DAT the incidence of anthracnose had high relative heterosis and heterobeltiosis. The enzyme polyphenol oxidase had highest heterosis followed by capsaicin and oleoresin for both type of heterosis. From the present investigation several promising three way cross hybrids were obtained with regard to fruit yield, yield attributes and resistance to anthracnose. Some of the promising three way cross hybrids are Jwalamukhi x Kidangoor local x Jwalasakhi, Jwalamukhi x Ujwala x Vellayani Athulya, Jwalamukhi x Ujwala x Kidangoor local, Jwalasakhi x Vellayani Athulya x Kidangoor local, Samkranthi local x Vellayani Athulya x Kidangoor local, Vellayani Athulya x Kidangoor local x Samkranthi local, Vellayani Athulya x Ujwala x Jwalamukhi, and Kidangoor local x Ujwala x Jwalasakhi. These can be directly used as hybrids or can be subjected to selection of superior types in the segregating generation to obtain stable varieties. The estimation of genetic components revealed the predominance of dominance x dominance gene effect for fruit yield per plant, number of branches per plant, number of fruits per plant, average fruit weight, fruit length, fruit girth, harvest index and capsaicin while the remaining traits days to first flowering, plant height, number of seeds per fruit, hundred seed weight, incidence of anthracnose, enzyme activity, phenol, oleoresin and vitamin C had additive x dominance type of epistatic effect. Heterosis method of breeding could be followed for the improvement of the traits which had dominance x dominance type of epistatic effect whereas the traits with additive x dominance component could be improved thereby postponing selection to later segregating generations and following recurrent selection.
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172753