Introgression of a wild Arachis species into three botanical varieties of Arachis hypogaea L

Abstract

Several wild diploid Arachis species possess traits that would be useful in the improvement of the tetraploid cultivated peanut (Arachis hypogaea L.). Crossing incompatibility limits the use of some of these germplasm resources, ie. those species outside the section Arachis. The undescribed species A. spegazzinii Krap. & Greg. nom. nud. (GKP 10038, PI 262133) is cross-compatible with A. hypogaea and species of other sections of the genus. GKP 10038 was evaluated as a possible bridge species for use in transferring characters from other species to the cultivated peanut. Two F3C3 plants of the allohexaploid A. spegazzinii x A. hypogaea (GKP 10038 x Spantex) were backcrossed to cultivars ('Spantex', 'New Mexico Valencia A', and 'Virginia 72 R) representing the three common botanical varieties of A. hypogaea. Backcrosses to Spantex were more easily made than those with the other cultivars. Sixteen backcross F1 plants were produced. Some sterility was encountered among the F1 plants but was more serious in the F2 generation. Somatic chromosome number was determined for parental, F1, F2, and F3 generations. Two of 24 F3 plants examined were found to have 40 chromosomes, the chromosome number of A. hypogaea. Meiotic behavior of the backcross F1 indicated that transfer of germplasm from GKP 10038 to A. hypogaea was possible. Morphological characters (flowers, fruit form and foliage) demonstrated the presence of portions of the GKP 10038 genome in its progeny. Combinations of agronomically desirable characters were commonly found in the F3 generation.