Morphological and reproductive characterization of nascent allotetraploids cross-compatible with cultivated peanut (Arachis hypogaea L.)

Abstract

Peanut improvement is limited by a narrow genetic base. However, this obstacle can be circumvented by incorporating phenotypic variability from wild, diploid Arachis species through interspecific hybridizations. In this study, four allotetraploid interspecific hybrids IpaCor4x (A. ipaensis × A. correntina), IpaDur4x (A. ipaensis × A. duranensis), IpaSten4x (A. ipaensis × A. stenosperma), and ValSten4x (A. valida × A. stenosperma) were created and morphologically characterized through the following parameters: flower count, flower size, flower banner pigmentation, leaf area and weight, leaf hairiness, main stem height, internode length, percent of reproductive nodes, biomass, 100 pod weight, and 100 seed weight. For every trait, except for flower banner absorption at 380 nm, at least one or more allotetraploids differed from the cultivated peanut control. In general, these allotetraploids had a greater production of flowers during the growing season, larger flowers, larger and hairier leaves, taller main stems, longer primary laterals, longer internodes, lower percentage of reproductive nodes, heavier plant body masses, and smaller seeds and pods. This phenotypic diversity can be utilized directly in ornamental and forage breeding, while for oil and food crop breeding, this diversity will likely need to be selected against while desirable traits such as disease and insect resistance and abiotic stress tolerances derived from the wild diploid species are maintained.