“Estimation of Gene Effect and Combining Ability” (Seminar Synopsis)

UNIVERSITY OF AGRICULTURAL SCIENCES, BANGALORE

DEPARTMENT OF GENETICS AND PLANT BREEDING

M.Sc. Seminar - GPB 581 (0+1)

“Estimation of Gene Effect and Combining Ability”

Plant breeding aims to improve crop varieties for higher yield, disease resistance, stress tolerance, and quality traits. Understanding the genetic basis of these traits is crucial for designing effective breeding strategies. Two key genetic principles in plant breeding are gene effect estimation and combining ability analysis, which helps breeders predict how traits are inherited and determine the best parental combinations for hybrid development. Gene action is measured in terms of genetic variance components. There are three types of genetic variance: additive, dominance, and epistatic variance.

The simple scaling tests (Mather, 1949; Hayman and Mather, 1955) and joint scaling test (Cavalli, 1952) followed by generation mean analysis (Jinks and Jones, 1958) provide a more precise assessment of variability by studying gene action and effects. Concepts of GCA and SCA have had an important influence on inbred line evaluation and population development in crop breeding. Several techniques are suggested for the estimation of combining ability. These include top cross, poly cross, diallel cross analysis, line × tester analysis, partial diallel cross, North Carolina design, and triallele cross, which are used to estimate combining ability.

Rain-fed rice farming in Kilifi, Kenya, faces challenges due to erratic rainfall and poor infrastructure. An analysis of combining ability identified Dourado Precoce as the most effective general combiner for early maturity, while Supaa, Komboka, and NERICA 10 demonstrated superior yield performance. In castor, genetic effects on seed yield were examined using 21 generations from two crosses, highlighting significant epistatic interactions and linkage effects.

Estimating gene effects and combining ability helps to identify superior parent lines and optimize breeding strategies for improved yield, maturity, and adaptability. This knowledge enhances hybrid development, leading to resilient, high-yielding crop varieties that support food security and sustainable agriculture.

REFERENCES

1. FASAHAT. AND PARVIZ., 2016, Principles and Utilization of Combining Ability in Plant Breeding. BBIJ., 4(1): 1-24

2. DIANGA., AL-IMRAN., KAMAU., JOSEPH., MUSILA. AND RUTH., 2020, Analysis of Combining Ability for Early Maturity and Yield in Rice (Genus: Oryza) at the Kenyan Coast. Int. J. Agron., 2020(1): 6230784

3. DELVADIYA., INDRAJAY., MADARIYA., RAJESHKUMAR., GINOYA, A. AND PATEL, J., 2024, Uncovering the inheritance mechanisms of yield and oil content in castor (Ricinus communis L.): a 21-generation study. Euphytica., 220(2): 20