Comparative Study On Growth Development And Yield Of Different Maturity Canola Varieties In Early And Late Sowing Date

With transferring the rural labor force,labour costs rose.Rape on direct seeding develop rapidly. Season contradictions between crop and double-crop rice become more prominent.It is great significance for developing rapeseed production and stable rape planting area to choice late sowing and early precocity rape varieties.In different Sowing conditions, In this paper, we disscussed the requirement of temperature in the growth and development stage and morphological and physiological indicators, differences in yield components of14different maturity characteristics of Brassica napus varieties (lines) in this article,In order to provide a scientific basis for the different maturity rape cultivation.1.According to the length of whole growth period of three years performance,14different rapeseed varieties is divided into early, middle and late, three types of ripe stage. The Qinza NO.7, Zhongyou NO.116,28-2010belong to the early maturity varieties, Ningyou NO.16, Zhongshuang NO.11belong to the late maturity varieties.The Qinza NO.7belongs to special early-maturing type in early maturity varieties, this variety enters flower bud differentiation at the3leaf stage, sowing seeds on October1-6th in Wuhan area, it can enter the flowering in mid to late November. If sowing seeds date delayed to October30th to November3th, then the flowering date will not be before winter, but the date of maturity still5-7days in advance compared with mid ripe varieties, the yield can reach2400kg per hectare, so this early maturity varietiesis worth of popularization and application in area of the triple-cropping system in The Yangtze river basin. According to temperature calculation in Wuhan,The Qinza No.7Suitable seeding time is after October14th.2. it will be obvious differences in growth period between early and late sowing dates, especially the differences in the days and active accumulated temperature of seedling stage between early maturing varieties and late varieties.The days number of seedling of early variety Qingza NO.7is30-39d in early sowing conditions,28-2010is51-72d, Zhongyou NO.116is55-64d, other varieties is121-137d, The seeding of Zhongshuang11A*73290is83d, but the days of bud stage is73d.Early variety with short features at seedling stage, bud stage and florescence tends is longer, in early sowing condition, Qingza NO.7,28-2010and Zhongyou NO.116seedling active accumulated temperature are between530℃～919℃, other late-maturing varieties active accumulated temperature is between1000℃～1300℃, in late sowing condition, the active accumulated temperature is between600℃～1300℃。Main factors lead to the differences is different varieties have different temperature susceptibility during vernalization and growth and development stage.3.The number of leaves and plant height difference was obvious in different maturity varieties.The leaf number of early varieties during the whole growth period was less thanlate-maturing varieties,on the early sowing conditions the leaf number of early-maturing varieties on average was less6.4pieces than late-maturingvarieties,on the condition of late sowing, the leaf number of early-maturing varieties on average was less2.8pieces than late-maturing varieties. The early-maturing varieties’ height was lower than late-maturing varieties,on the condition of early sowing,plant height on average was lower23.9cm. under the conditions of late sowing,plant height on average was lower8.5cm. Plant dry weight and accumulated temperature relationship was first slow-fast process, Speed of different Maturity varieties ware different, hybrid dry weight accumulation faster than conventional varieties, dry weight accumulation in early sowing conditions faster than late sowing conditions.4.Following plant differentiation, bolting and flowering, the the soluble sugar content in the functional leaf showed a tendency to increase, it also increased at low temperature stage in winter. In the early sowing condition, the soluble sugar of the early-maturing variety reached a maximum in the flowering stage, but the stage of late-maturing variety was the bolting stage; In the late sowing conditions, the maximum of all the variety soluble sugar appeared in the bolting stage, it was low at the flowering stage. The overall Changing trends of leaf soluble nitrogen content was drop at low temperatures stage of winter, rise at bud stage and reached its maximum(6-8) in flowering stage.then tend to drop. The range of functional leaf C/N was1～2,3～5at low temperature stage. The C/N had a tendency to increase at flower bud differentiation stage, bud stage and flowering stage, the value of C/N was0.274～1.133at full-bloom stage 5. There was no significant correlation between Yield and maturity,but the pod number per plant of early maturing varieties was more than the late-maturing varieties. In the early sowing conditions, the average pods number per plant of the three early maturing varieties was301for Qingza NO.7,28-2010and Zhongyou NO.116, but the average pods number per plant of Zhongyou NO.7819、Zhongshuang NO.11and Ningyou NO.16was only194. Sowing date affected the pods per plant of the early maturing varieties, the appropriate early seeding could increase the pods per plant of early-maturing varieties, and the difference reached a significant level.