昆明自然条件下利用小麦×玉米诱导小麦单倍体的研究初报

Preliminary Study on Using Wheat×Maize to Induce Wheat Haploid Plant in Natural Condition of Kunming

为建立昆明自然条件下产生小麦单倍体的技术体系，将6个小麦材料和3个玉米材料在昆明自然条件下分期播种，并进行小麦×玉米杂交试验。结果表明，在昆明自然条件下，小麦、玉米杂交可于5月中旬开始，10月中旬结束，持续期长达6个月；由于玉米花粉充足，采用“滚粉”法授粉，可显著提高授粉效率，杂交颖果结实率达88．77％～98．4％；授粉后睛好天气下的颖果结实率和得胚率分别为88．77％和19．94％，是阴雨天的2倍以上；田间取穗剥胚时间以授粉后17～19d为宜，此时80％以上的单倍体胚直径均在0．5mm以上．部分已有初步分化；发育饱满的颖果得胚率平均为24．8％，是干瘪颖果的2．95倍；单倍体胚培养的幼苗在昆明不需越夏，5月中旬到6月中旬杂交获得的单倍体苗移栽加倍后一般可于当年9～11月收获加倍单倍体种子。因此昆明的自然条件可为利用小麦×玉米大量诱导小麦单倍体提供便利，同时也有利于通过大量试验进一步完善该技术。

In order to set up the protocols of wheat X maize for wheat breading and genetic analysis, 22 sowing dates of 6 wheat materials and 11 sowing dates of 3 maize varieties were conducted in the field from February 9 to August 22, 2003 in Kunming, and the crosses of wheat× maize were made. Results showed that there were 6 months to conduct wheat X maize in natural conditions of Kunming every year from middle May to middle October. In pollination, ＇rolling pollens＇, a modified method ofpollinating by rolling one or several emasculated wheat ears into the collected fresh maize pollens, was adopted because large amount of maize pollens could be collected, which obviously raised the effectiveness of pollination at about 10-15 spikes/min per person, and the rate of caryopsis could be up to 88.77%-98.4%. The average daytime relative humidity （RH） of atmosphere in 10 days after pollination had significant effects on caryopsis and embryo rates, on average, 88.77% and 58.45% of caryopsis rate, 19. 940/40 and 6.55% of embryo rate were achieved under lower （RH〈70%） and higher relative humidity （RH〉85%） respectively. The optimum time for harvesting spikes under natural conditions in Kunming was at 17-19 d after pollination, when 80% of haploid embryos were larger than 0.5mm in diameter, with preliminary differentiation in some bigger ones. And haploid embryosproduced in plump caryopses was 2.95 times of that in shrivelled or blighted ones, 24.80/00 and 8.40/40, respectiveoly. Haploid seedlings with 2 leaves could be transplanted into field whenever produced in Kunming all the year and double haploid seeds from plants treated with colchicine could be harvestedfrom September to November if crosses the natural conditions in Kunming could plants induced with maize pollen. were made between middle May provide good conditions for mass to middle June. Therefore, production of haploid wheatplants induced with maize pollen.