Sclerotinia resistance in sunflower. II. Combining ability and midparent heterosis for reaction to ascospore infections at flowering

• Published in: Euphytica 2012-11, Vol.188 (2), p.299-307
• Main Authors: Godoy, Marcela, Castaño, Fernando, Ré, José, Rodríguez, Raúl
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Ascospores; Biological and medical sciences; Biomedical and Life Sciences; Biotechnology; Combining ability; Crops; Flowering; Fundamental and applied biological sciences. Psychology; Genetic control; Genetics and breeding of economic plants; Genotypes; Helianthus; Heterosis; Heterosis. Floral biology applications: apomixy, male sterility, incompatibility, varia; Inbreeding; Infection; Life Sciences; Mating; Parental behavior; Plant breeding; Plant breeding: fundamental aspects and methodology; Plant Genetics and Genomics; Plant Pathology; Plant Physiology; Plant Sciences; Sclerotinia; Sclerotinia sclerotiorum; Varietal selection. Specialized plant breeding, plant breeding aims; White rot
• ISSN: 0014-2336; 1573-5060
• DOI: 10.1007/s10681-012-0749-2

In Argentina, susceptibility of the sunflower crop to Sclerotinia sclerotiorum capitulum attacks can cause significant yield losses. We reported earlier two hybrids among a series obtained from crosses between inbred lines following a factorial mating design that had a sufficient level of resistance to be adapted to the main Argentina sunflower growing area. Results concerning the per se behavior of the parental lines involved in these crosses and the combining ability and heterosis effects of such parental genotypes are presented in this article. The lines showed different responses to white rot incidence and relative incubation period. There were significant effects for general and specific combining ability and also for midparent heterosis, for the two variables evaluated. Preponderance of additive gene effects on genetic control white rot resistance level was shown. The development of sunflower inbred lines to be used as parents in the production of hybrids for areas requiring moderately resistant hybrids is an important phase in breeding programs. To optimize the use of resources and time, our results suggest that testing general combining ability at early generations of selfing followed by testing of hybrids may be considered as an adequate strategy in breeding for white rot resistance.