Analysis Of Agronomic Characters In Different Sowing Date And Cold Resistant Physiology In Winter Wheat

Frost damage in winter and cold injury in spring are the serious hazard of winter wheat inhuanghuai area. Twelve different type of winter wheat cultivars were chosed which werewidely planted in huanghuai wheat production zone, all of cultivars were planted at foursowing date, study on sowing date influence to agronomic characters, and cold resistantphysiology in jointing stage, explore the relationship between frost resistance in winter andcold-resistance in spring of wheat varieties. The results are as follows:(1) Cold hardiness differences of the different cultivars in wintering to green stageIn wintering, antioxidant enzyme(SOD) activity and osmoregulation substances contentof winterness Shan229and Yannong19were the highest, membrane lipid peroxidationproduce(MDA) content was the lowest, the frost resistance of them were the best; frostresistance of semi-winterness Huaimai20, Wanmai38and Xinong979was slightly worsethan the winterness varieties; SOD activity, osmoregulation substances content of springnessZhengmai9023, Xiaoyan22and semi-winter Zhoumai18were low, its chilling resistance ofmembrane was high, frost resistance in winter was poor. In green stage, cold resistanc of allvarieties decreased in different degree, cold resistance of semi-winter Huaimai20, Wanmai38and winterness Shan229were best, cold resistance of Yannong19was slightly worse thanthem; cold resistance of springness varieties was worst, cold hardiness of Zhengmai366andShanmai139decreased significantly.(2) Influence on sowing date to cold resistance in winteringCold resistance of different varieties was different at four sowing date in wintering.Antioxidant capacity and membrane cold stability of springness Zhengmai9023, Xiaoyan22and semi-winter Zhoumai18enhanced with sowing date delayed, osmoregulation substancescontent of them was increased, it means with sowing date postponed, frost resistance of themwas strengthened. If winterness Shan229and Yannong19have good frost resistance inwintering, the best seeding time of was in the early and middle october, in this condition theirability of antioxidant capacity and membrane cold stability were well, substances related withcold resistance content was more. Frost resistance of others semi-winter varieties was good ifthey were planted about mid-october.(3) Influence on sowing date to process of spike differentiation of jointing stage in different varietiesInfluence on sowing date to process of spike differentiation of jointing stage in differentvarieties. With sowing date delayed, duration of floret to anther separation of all varietiesbecome shorter, growth period was significantly shorter. There are differences in spikedifferentiation process of different varieties, springness Zhengmai9023, Xiaoyan22andsemi-winter Jimai22, Zhengmai366raise faster in green stage, but development more slowlyin late jointing stage, especially duration of anther separation was long, its maybe thesignificant reason of they have bad anti-spring cold bility. The frost resistance winternessYannong19was very good, and the anti-spring cold bility was good also, but it raise slowlyin early spring, grow faster in late jointing stage, it could development into anther separationafter frostbite low temperature, so Yannong19was classified the typical eavde spring coldvarietie.(4) Influence on sowing date to agronomic charactersWith sowing date delayed, Plant height of all varieties were decreased differently, lengthof uppermost internode decreased in large amplitude among which, and spike length becomeshorter gradually, spike length declined obviously in the third and fourth sowing date, Fromthe beginning of the third sowing date, the neck length of spike declined. Number of singlepanicles,1000grain weight decreased obviously with postpone sowing date, compared withthe first sowing date, number of single panicles of the second, third and fourth sowing datewas declined separately3.5,6.4,8.3, and1000grain weight decreased separately1.2g,1.6g,2.8g.(5) Cold resistant physiology at wintering and different stages of jointingIn wintering stage: Pro content, WSS content and SOD activity of winterness Shan229and semi-winter Wanmai38and Huaimai20were high, but MDA content was lower,physiological indexes of springness Xiaoyan22were opposite, other cultivars was in themiddle; all of cultivars frost resistance were: Shan229, Wanmai38, Huaimai20were superiorthan semi-winter cultivars Xinong979, Shanmai139and Zhengmai366, semi-winterZhoumai18and springness Xiaoyan22were the last.However, in jointing stage, Cold resistant physiology of Shan229, Wanmai38, Huaimai20, Xinong979were better, and their cold-resistance in spring were better than other cultivars;SOD activity, WSS content of Shanmai139and Zhengmai366were lower in both natural andartificial low temperature, and their ability of anti-spring cold was poor, it could speculate thatSOD activity may be considered as anti-spring cold sign.Although SOD activity and WSS content of Xiaoyan22were low, its Pro content was thehighest in the vicinity of anther separation stage, Pro content of Zhoumai18was higher than other cultivars in floret initiation after natural drop in temperature, these may be latent causesthat the cold-resistance in spring of Xiaoyan22and Zhoumai18were better than that ofShanmai139and Zhengmai366. Frost resistance in winter and cold-resistance in spring wasinconsistent in wheat varieties, which indicate that there are differences in physiologicalmechanism of cold hardiness between wintering and jointing stage, also cold-resistance inspring may be synergically regulated with physiological material.