| Hybrid rapeseed has a large potential to increase yields,but seed purity limits its yield levels.Chinese rapeseed hybrids are mainly produced by the Polima Cytoplasmic Male Sterility.The main factors influencing the purity of cytoplasmic trilineage seed production are the purity of the parents,the length of time between floral encounters,and the stability of the sterility lines.Shaanyou28 is a hybrid produced by mating the Polimar triple line with the parental combination 9024A/1521 C.Studies over the years have shown that it suffers from unstable fertility in production and to a certain extent the parents’ flowering periods do not meet.In response to these problems,this experiment is intended to study the adjustment of row ratios,the regulation of flowering time by picking shoots and the control of trace pollen by chemical hybriding agents,etc.Finally,each individual technology will be integrated to improve the purity of hybrid seed production and provide a theoretical reference for Shaanyou 28 hybrid seed production.The main results are as follows:1.Row ratio has an effect on seed yield.The results of the comparison of 9024 A agronomic traits under different parental row ratios showed that a suitable number of parental rows at maturity could improve seed production when the parental row ratios were the same.The yield of 9024 A at different row ratios was 1 : 2 > 2 : 4 > 2 : 3 > 1 : 3.In terms of yield per plant,1 : 2 was better than 2 : 4,and 1 : 2 yielded more per acre when considering the number of mother plants planted per acre.However,in practical terms,2 : 4is more conducive to farming operations.Therefore,on the whole,a row ratio of 2 : 4 is more suitable for the production of the Shaanyou 28 hybrid.2.Picking shoots can delay the flowering period of rape and reduce micropollen,while the right length can also achieve some yield increase.Changes in flowering time,micropollen plant rate,agronomic traits and yield of 9024 A were compared with each other under different plucking lengths.3.Both AS1 and 75% tribenuron-methyl were effective in controlling trace pollen.The results of the different concentrations of AS1 and 75% tribenuron-methyl showed that AS1 at 160 m L/15 L and 190 m L/15 L had less trace pollen and a high rate of abortive and dead pollen,while the number of main inflorescence siliquas,the effective number of siliquas per plant and the number of grains per siliqua were not greatly affected;The overall performance of 75% bensulfuron was better when diluted 100 times,however,the effect on the number of corners of its main inflorescence,the effective number of siliquas per plant and the number of grains per siliqua was too great and could cause a decrease in its seed production.Therefore,for seed production,AS1 can be sprayed at the bud stage of9024 A at a concentration of 160 m L/15 L to effectively control 9024 A trace pollen and reduce the possibility of self-fertilisation,with less impact on the plant,while ensuring yield.4.The agent EX was more effective in killing males.In this experiment,three agents,EX,AS2 and EXP,were selected and sprayed on 20 materials in five gradients,followed by a field survey of the 20 materials for fertility changes,pollen viability identification and self-fertility statistics.The results showed that EX was more effective in killing males among the three agents,causing sterility in eight materials for≥20 days,pollen defeat in12 materials at 90% or more,and self-fertility in 11 materials at 10% or less;AS2 rendered nine materials sterile for 20 days or more,three materials sterile for 90% or more,and six materials with a self-fertility rate of less than 11%;EXP had no significant male killing effect on 20 materials. |
PDF Full Text Request