Reproduction of the Three-line Genic Male Sterile Line Parent Mian 7MB-1 （Brasscia Napus L.） and Seed Production of F1 Based on Somatic Tissue Culture

[Objective] The aim was to study the reproduction of the three-line genic male sterile （GMS） lineparent Mian7MB-1 （B. NapusL.） and the seed production of F1 through somatic tissue culture. [Methed] Through hybridization, a new breeding material Mian 7MB-1 in three-line genic temporary maintainer line propagated by tissue culture was used to improve the sterile plant rate of rapeseed in dual-purpose recessive GMS line, such as Mian 7AB type, S45AB type, and etc. And then the variety comparative test was performed. [Result] In order to avoid some fertility restoration phenomena occurring during the process of self-reproduction, Mian 7AB was propagated in bulk with somatic tissue culture of temporary maintainer line plant stem. The propagated temporary maintainer line seedlings were applied to the breeding and seed production of net room male sterile line parent, promoting the sterile plant rate of the male sterile line parent to 91.7% -93.5%. The male sterile line parents per hectare were enough for the seed production of hybrid F1 in 7 500 -15 000 hm^2. [ Conclusion ] Compared with the original dual-purpose GMS line, the seed production ultilizing male sterile line with high sterile plant rate greatly reduced the labor, significantly improved the seed yield, ensuring the seed quality and forming a perfect breeding and seed production system.

Production of Partial New-typed Brassica Napus by Introgression of Genomic Components from B. rapa and B. carinata

A breeding strategy for widening the germplasm of Brassica napus was proposed by introgression of the A^r subgenome of B. rapa （A^rA^r） and C^c of B. carinata （B^cB^cC^cC^c） into natural B. napus （AnAncncn）. The progenies with 38 chromosomes that were derived from the self-pollinated seeds of pentaploid hybrids （A^rA^nB^cC^cC^n） were used for further research. Some of the partial new-typed B. napus showed normal meiotic behavior, high portion of germinated pollen and normal embryological development. This indicates that the selected new-typed B. napus had a balanced genetic base. Molecular analysis showed that about 50% of the genome in the new-typed B. napus was replaced by A^r and C^c subgenome from B. rapa and B. carinata. Considering the genetic diversity among different lines of new-typed B. napus, it was deduced that the introgression of the genomic components from B, rapa and B. carinata could widen the genetic diversity of rapeseed.

Effects of Nitrogen Fertilization on the Growth and N Uptake of Late-sowing Winter Oilseed Rape (Brassica napus L.)

[Objective] The aim of this work was to analyze the N fertilization on the vegetative growth and N uptake of different winter rapeseed varieties at wintering stage. [Method] In two consecutive years （2009-2011）, two winter rapeseed varieties （B. napus L.）, an early maturity variety Zhongyou 116 （ZY116） and a middle-late application maturity variety Zhongyouza 12 （ZYZ12） were employed. Field experiments with different N levels （0, 90, 180, 270, 360 kg N/hm 2 ） were designed. At the wintering stage, the dry matter weight, the nitrogen content and concentration of plants, leaf nitrate reductase activity （NRA） and seed yields were investigated. [Result] The shoot dry matter of ZY116 increased rapidly when N rate ranged from 0 to 180 kg/hm 2 , and it raised slightly when N rate ranged from 180 to 360 kg/hm 2 . The shoot dry matter of ZYZ12 were changed in a single peak curve; the peak of shoot dry matter appeared at 270 kg N/hm 2 . The N concentration and N content in shoot and root increased rapidly when the N rate changed from 90 to 180 kg/hm 2 . Moreover, the N concentration and N content root of in ZYZ12 were much higher than that of ZY116. Present study revealed that the changed trend of leaf nitrate reductase activities （NRA） were significantly increased at the N rate of 180 kg/hm 2 in ZY116 and ZYZ12 compared with the N rate of 90 kg/hm 2 in two years. [Conclusion] Optimal nitrogen application significantly increased the dry weights and N uptake at wintering stage as well as increasing the yield of winter oilseed rape.

双低油菜湘油15(B.napus)对菌核病抗性的研究

经苗期菌丝块接种鉴定和花期带菌牙签鉴定表明 ,双低油菜湘油 15对菌核病有高抗性。当病原危害后 ,湘油15体内酚类物质含量和几丁质酶活性迅速升高 ,且维持时间长 ,湘油 15与感病品种 98C4 0和中抗品种中油 82 1杂交后代抗性表现为双亲平均值 。

Preliminary investigation and detection based on loop-mediated isothermal amplification(LAMP)of phytoplasmas associated with diseases in B.napus L.

In the last decade,some disease occurred on our experimental farms that had caused serious losses.They were not caused by fungi,bacteria or viruses.By loop-mediated isothermal amplification(LAMP)technique,the detection results pointed to the possible pathogen as phytoplasma.The investigation results implied that phytoplasmas could cause more than 13 kinds of symptoms in almost all parts of plants in B.napus L.,including witches’broom,multi-stems,aggregate main inflorescences,and flat stems.The incidences of these phytoplasma-associated diseases in our experimental farms rose from 1.61%in 2010 to 6.00%in 2021.Some phytoplasma infected plants died without any growing points.These studies would be helpful for detecting phytoplasmas diseases,selecting disease resistant germplasm and improving varieties with disease resistances in B.napus L.

Nitrogen Metabolising Enzymes and Photosynthetic Pigments as Influenced by Nitrogen Application in Oilseed Rape(Brassica napus L.)

Nitrogen(N)assimilation is a wide pathway in plants because of its fundamental importance for growth and development.The transport,assimilation and recycling of nitrogen is a highly complex and regulated process,as it is the mineral nutrient that is required in great abundance by the plants.Basic approach to enhance agriculture sustainability is dependent on exploration of the elite germplasm where new cultivars could perform better even under low N.To test the effect of nitrogen levels at 100 and 125 kg ha-1 on photosynthetic pigments and N assimilation in oilseed rape(B.napus L.)canola variety GSC-7 and hybrid Hyola PAC 401 were selected for comparison with new hybrid PGSH-52 in pipeline.N assimilating enzymes were assayed at vegetative,flowering and siliquing stages of crop growth to visualise the impact of N on the productivity.Nitrogen assimilating enzymes were highest at flowering stage and enhanced with increased N level.Nitrate reductase(NR)activity improved by 11.5%,nitrite reductase(NiR)by 24.2%,glutamine synthetase(GS)by 12.2%and glutamate synthase(GOGAT)by 35.2%over recommended N dose(N100)at flowering stage.Hyola PAC 401 registered maximum enzymatic activities trailed by GSC-7 at all the three stages of crop growth.Differences existed within the genotypes for photosynthetic pigments which varied with N levels.Chlorophyll a,chlorophyll b,total chlorophyll and carotenoids increased with nitrogen at 125 kg N ha^(-1)whereas chlorophyll a/b declined at three stages of crop growth.At flowering total chlorophyll and carotenoids were maximum and enhanced by 12.8%and 5%respectively with higher nitrogen level.