Efficient selection intensity in early generation index selection in groundnut (Arachis hypogaea L.)

Area of Science:

• Plant breeding and genetics
• Agricultural science
• Crop improvement

Background:

• Evaluating the breeding potential of F2 generation plants is crucial for crop improvement.
• Selection indices are vital tools for identifying superior genotypes in segregating generations.
• Understanding the genetic basis of yield and physiological components aids in developing effective selection strategies.

Purpose of the Study:

• To assess the breeding potential of F2 generation plants from single and three-way crosses.
• To compare the efficacy of selection indices based on yield components versus combined physiological and yield components.
• To determine the optimal strategy for selecting F2 plants that yield superior F3 families for pod number.

Main Methods:

• Development and application of selection indices using percentage improvement of F2 over the better parent.
• Ranking F2 plants based on a regression index to create a ranked F2 distribution (FRD).
• Evaluation of F3 family performance derived from different FRD quartiles (T25, T50, T75, T100).

Main Results:

• F3 families from the top 25% (T25) of F2 plants showed a higher frequency of selection for pod number compared to other quartiles.
• Three-way crosses yielded a higher frequency of selections than single crosses.
• Selection indices incorporating both physiological and yield components were more effective than those using yield components alone.

Conclusions:

• Selection strategies combining physiological and yield components in F2 plants enhance the efficiency of identifying superior F3 families.
• Three-way crosses offer advantages over single crosses for improving pod number frequency.
• Bunch x bunch crosses are recommended as a valuable complement to bunch x runner crosses in breeding programs.