title: Efficient selection intensity in early generation index selection in groundnut (Arachis hypogaea L.).
abstract: The F2 potential of single and three-way crosses was evaluated using a set of physiological and yield components. Results were based on an index of selection using (a) only yield components and (b) both physiological and yield components. The indices were constructed using the percentage improvement of F2 over the better parent of the corresponding F1 cross for every character. The performance of F2 plants assessed by the expected value of the regression index was ranked in descending order to provide a ranked F2 distribution (FRD). The FRD was divided into four equal parts, T25 (top 25%), T50 (26-50%), T75 (51-75%) and T100 (76-100%). F3 families derived from F2 plants in T25 were found to provide a higher frequency of selections for pod number than T50, T75 and T100. The frequency of selections was higher in three-way than single crosses. Selection index based on physiological and yield components was more efficient in trapping F2 plants providing selections in F3 than the index based on yield components only. The results brought out the importance of bunch x bunch crosses as a complement to the usually advocated bunch x runner ones.
authors.affiliation: Regional Station, Indian Agricultural Research Institute, 500 030, Rajendranagar, Hyderabad, India.
authors.forename: A
authors.initials: A
authors.lastname: Bandyopadhyay
authors.forename: V
authors.initials: V
authors.lastname: Arunachalam
authors.forename: K
authors.initials: K
authors.lastname: Venkaiah