核不育两系法制种最大的缺点是由于核不育基因的遗传特点使保持系与不育系无法分开，通常制种时需要在蕾期将母本分离出的50%可育株识别并拔除，增加了制种成本和纯度风险。本研究利用中亚热带特殊冬暖、冬春干旱条件，在棉花核不育系作母本制种时，第1年剔除其中50%的可育株制种后，将不育株宿根越冬，第2年作为完全不育株用于制种。2006—2011年调查了不同宿根年限、冬季间套短季蔬菜、不同修剪时间和修剪方法对棉花宿根制种的影响。结果表明，棉花宿根后生长期延长，较同期播种的实生苗提前10 d 进入生殖生长，单株结铃数显著增加，单铃重略有下降。宿根1~2年其产量比不宿根高10.3%~5.9%，第3年略降低但不显著，第4~第5年显著减产9.4%~14.0%。随着宿根年限的延长，植株基部老根明显畸形。在5年以内宿根株凋亡率与宿根年限及土地类型的关系不显著，但与土壤水分含量及修枝方法有关。最佳的宿根方法为，冬季棉行不间种作物，不修枝，槽平地于灌水时(3月中下旬)，坡台地于旱季结束的第一场雨后(6月初)，在地面高10 cm 处将主茎及其下部发出的早期再生芽贴近主茎剪除，然后保留新发出的一级再生芽1~2个并进行水肥管理。%It is hard to separate maintainer line and sterile line in two-line-system hybrid breeding, so half of the fertile plants derived from maternal line should be pulled out at bud stage, which increases the cost of seed production and the risk of hybrid seed purity. In this research, taking advantage of specific weather conditions of warm winter and dry winter-spring season in the mid-subtropical zone, we explored hybrid seed production with overwintered perennial sterile plants after eliminating the 50%fertile plants from the nuclear sterile line in the first year. From 2006 to 2011, we investigated various factors that might influence hybrid seed production with perennial cotton sterile plants, including different ages of perennial root, winter-season intercropping of rapid cycling vegetables, pruning times and pruning methods. The results indicated that the perennial plants had extended growth period , its reproductive growth stunted 10 days earlier than that of seedlings with corresponding sowing time, its boll number per plant was significantly higher, while boll weight was slightly lower. The hyrid seed yield in first- and second-year perennial plants was 10.3% to 5.9% higher than that in one year plants. The yield showed non-significant reduction in the third year of prennial production, but significantly reduced by 9.4% to 14.0% in the fourth to fifth years. With the increase of overwintering years, the old root at the basal portion of the plant showed obvious malformation. Within the first five years, the death rate of perennial plants had no relationship with ages of perennial root and field types, but was related to soil water content and pruning methods. The best way for perennial root onverwintering was: no intercropping between winter cotton lines and othen crops, no pruning, and leaving the cotton plants in the field for natural overwintering. In the next year, the main stem and early regenerated buds should be pruned at 10 cm above the ground before the rainy season or the first irrigation, then one or two regenerated primary buds should be reserved with water and nutrition managements.
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