Stable Production of Wheat Haploid and Doubled Haploid by Wheat × Maize Cross

Abstract

One of the most effective ways to produce wheat haploid is the method of crossing wheat with maize. However, the problem of unstable frequencies in haploid and doubled haploid production affects its application. In this study, 13 wheat F1hybrids crossed with maize to explore the effects of wheat growth condition, hormone treatment, culture medium, and strong seedling treatment on production of haploid and doubled haploid. The frequency of embryo formation was 23.9% and the number of embryos per spike was 6.8 for the wheat plants grown in filed and then detached before pollination and hydroponically cultured after pollination. The efficiency of this method was three times higher than that of the method with plants transplanted into pot after green recovering in early spring and then grown in the unheated greenhouse condition. Embryo formation frequencies were obviously different among wheat crosses. There was no significant difference in the frequency of embryo formation between treatments of dipping spike with Dicamba(21.5%) and 2,4-D(21.1%). However, wheat cross had significant effect on embryo formation. The mean frequency of embryo germination on B5medium was 82.0%, ranging from 70.9% to 88.3%, whereas averaged frequency of embryo germination was 76.6% on 1/2 MS medium, ranging from 70.0% to 86.0%. There was no significant difference between the two culture media in embryo germination. The efficiency of doubled haploid production for the seedlings treated with culture medium and transplanted into pot was 67.6% and 8.6%, respectively. Most of seedlings transplanted into pot had no tiller and grew weakly; this is the reason for low frequency of survival plant and very low frequency of doubling after colchicine treatment.