Study on the culture of cut plants in wheat haploid embryo induction by a wheat × maize cross

Abstract

The wheat × maize system is one of the most effective ways to produce haploids in wheat. Whether and how it could be successfully applied in practical breeding mostly depends upon the efficiency of haploid embryo production. To perfect the protocols of haploid embryo induction, the efficiency of haploid embryo production between in vitro culture of cut plant and intact plant growth for hybrid spikes with two F₁ wheat hybrids and two maize varieties was compared. Effects of different cutting plant times and formulas of nutrient solutions for cut plant culture on haploid embryo formation were also studied. Results indicated that the embryo rate of in vitro culture was 3.29 times that of intact plant growth, with the figures of 31.6% vs 9.6%, respectively. The optimal time for cut plant culture was 24 h after pollination. Formulas of nutrient solutions significantly affected the efficiency of haploid embryo induction. With an embryo rate of 0–35.5%, adding calcium phosphate in the culture solution at 3 g·L^-1 could raise the caryopsis and embryo rates. According to this study, the best medium for cut plant culture was: 100 mgL^-1 2,4-D + 40 gL^-1 sucrose + 10 mgL^-1 silver nitrate + 8 mLL^-1 sulfurous acid + 3 gL^-1 calcium phosphate, with which a caryopsis rate of 95% and an embryo rate of about 30% could be obtained.

Keywords

wide cross between wheat and maize / in vitro culture of cut plants / haploid embryo induction