Doubled Haploid Production Using an Improved Anther Culture Protocol for Sorghum [Sorghum bicolor (L.) Moench

Abstract

Sorghum [Sorghum bicolor (L.) Moench] can benefit from accelerated breeding and release of improved varieties through doubled haploid technology. The technology has been used in speeding up the breeding of other major cereals such as wheat, maize and rice, for which generally widely applied optimised protocols exist. A reproducible protocol for the crop, that can overcome genotype dependency and other species-specific challenges such as phenolic exudation is however lacking. This study aimed at sorghum doubled haploids production thereby contributing to the development of an improved protocol. From the 28 hybrid genotypes, both F1 registered- and experimental hybrids involved, this study successfully produced haploids from five genotypes and subsequently, four confirmed doubled-haploid lines on W14mf medium or its modification with 1.0 gl−1 L-proline, 1.0 gl−1 L-asparagine and 1.0 gl−1 KH2PO4. Medium 190-2Cu was used for regeneration and rooting, which occurred successfully, if the calli were transferred on to it less than 7 days after induction, and temperature was maintained at 25˚C under light condition. Genotype dependency was not wholly overcome; however, sorghum’s high tillering ability and abiotic stress tolerance were observed to contribute to attainment of haploid plantlets. Spontaneous diploids producing seeds at rates of upto 80.5% were obtained, therefore eliminating the need for colchicine duplication.