Derivation of interspecific Solanum hybrid genotypes with resistance to Colorado potato beetle (Leptinotarsa decemlineata Say)

Abstract

The anther culture response of diploid Solanum chacoense (chc) - S. phureja (phu) hybrids and the regeneration potential of anther-derived monoploids was evaluated. In vivo evaluation of interspecific hybrids was also performed. Three hybrids were anther cultured to observe the effects of reduced nitrogen source on androgenesis. Anthers were distributed to five reduced nitrogen sources. The N concentration was 30 mM. No tested reduced nitrogen source proved superior to the control. Genotype significantly affected embryo production. Eleven monoploid genotypes were included in a leaf disc regeneration procedure utilizing three separate transfers to fresh medium differing by growth regulator composition; six genotypes responded. Silver thiosulfate (STS) at either of two steps in the process proved detrimental to diploid recovery.

Hybrids between phu and chc involving six phu clones and eight chc clones or accessions, all resistant to Colorado potato beetle (CPB), were used. No inter-family differences for germination, fruit/pollination, or seed/fruit were observed. Substantial mortality, ascribed to the phenomenon of “hybrid breakdown”, occurred in three families by month four of the study. Field plantings revealed adequate CPB resistance, while Ambush (147 g/ha) application increased total tuber weight per plant and average tuber weight. Hybrids produced less total tuber weight than S. tuberosum (tbr), while chc genotypes produced the smallest average tuber size. Interspecific hybrids produced tuber sizes intermediate between chc and phu. Tbr tubers were the largest. Chc families, regardless of selection for leptine glycolakaloids, suffered the least CPB damage and phu parental clones and hybrid families suffered the most.