Description

Abstract: Short growing seasons, such as those that occur in semi-arid regions of West Africa, prevent peanut (Arachis hypogaea L.) from maturing properly. Immature fruit lowers peanut quality and yield, and enhances growth of toxin-producing molds during storage. Germplasm with expressed accelerated development for use as parents in developing early maturing (75 day) cultivars suited for production in those regions is limited. Information on the genetic variability for earliness among the very early maturing candidate parental lines is lacking. Five erect, early maturing peanut lines of diverse origin were crossed in diallel; and parent, F1, and F2 generation progeny from plantings on four dates were compared. Measures were made on a plant basis for the number of days from planting to emergence (DEMR), number of days to first (DONE), fifth (DFIV), tenth (DTEN), fifteenth (DFIFT), twentieth (DTWEN), and twenty-fifth (DTW5) flower; and, following early digging, for number of full-size pods (FULL), number of mature pods (NUMP), and percent mature pods (%MP). F2 segregates that emerged and flowered earlier than parental and F1 plants were noted. Coefficients of correlation for DEMR and flowers DONE to DTW5 with FULL, NUMP, and %MP were negative; the association being stronger with FULL and NUMP than with %MP. R values were highest for DTW5 with FULL and NUMP, and decreased progressively with lower flower numbers (longer time intervals between measures) which indicated that the developmental rate was not consistent among genotypes. Mean broad sense heritability estimates for the traits examined ranged from 36 to 45%. H estimates for specific reproductive stages on individual crosses ranged from 4 to 65%, but for no cross were the H values consistently high for all measures. Both General and specific combining abilities were insignificant. The frequency of F2 plants with FULL and NUMP extending the range of their parents was low. Opportunity for selection of recombinants that would produce large numbers of full-size and mature pods faster than that of the parental lines might be possible in some of the crosses. The extent of potential decrease in growth duration could not be estimated from this study.