A further evaluation of hybrid wheat

The development of F1 hybrid varieties of wheat is reviewed under four main headings: male sterility, hybrid seed production, the performance of hybrids and commercial aspects. The three systems for male sterility used in wheat (cytoplasmic male sterility, nuciear male sterility and chemical hybridizing agents) are described and it is noted that no system is without problems or has a clear advantage over the others. Hybrid seed production is considered from the basis of the reproductive system of wheat and if is concluded that major biological environmental constraints remain unresolved and conflict wifh the objective of a reliable supply of seed. A yield benefit sufficient to justify the cost of producing hybrid wheal seems remote at the present time. Indeed, trial results fend to support the hypothesis that heterosis in wheat arises from dominance with the additional factors of linkage and interaction of alleles. It is therefore concluded that the case for commercializing hybrid wheat is not strong unless biotechnology is able significantly to reduce production costs.