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Wheat hybrids have been widely demonstrated to have remarkable heterosis or hybrid vigor in increasing yield potential and stability since the 1960s. Two-line hybrid wheat can achieve higher yields than local varieties, especially in marginal environments. However, the commercial application of hybrid wheat is hindered by higher seed costs, primarily due to lower yields in hybrid seed production. Stigma exsertion has been verified as a decisive factor in increasing rice's hybrid seed yield, but more investigation is needed in hybrid wheat breeding and production. In this study, four thermo-photo-sensitive genic male sterile lines, including K41S, K64S, K66S, and K68S, with different stigma exsertion rates (SERs) were used to compare the differences in floral architecture relative to stigma exsertion over two growing seasons. The results revealed that the K41S and K64S exhibited a relatively higher SER at 21.87% and 22.81%, respectively. No exserted stigma was observed in K66S, and K68S had an SER of only 0.82%. This study found that the stigma length, glume width and the length–width ratio of the glume were significantly correlated with the SER, with correlation coefficients of 0.46, −0.46 and 0.60, respectively. Other stigma features such as the branch angle, stretch width and hairbrush length, as well as the glume length, also had a weakly positive correlation with SER (r = 0.09–0.27). For K41S and K64S, the SER was significantly affected by the differences in the stigma branch angle and stigma stretch width among florets. A cross-pollination survey showed that the out-crossing ability of florets with an exserted stigma was about three times as high as that of florets with a non-exserted stigma. As a result, the stigma-exserted florets that accounted for 21.87% and 22.81% of the total florets in K41S and K64S produced 46.80% and 48.53% of the total cross-pollinated seeds in both sterile lines. These findings suggest that a longer stigma combined with a slender glume appears to be the essential floral feature of stigma exsertion in sterile wheat lines. It is expected that breeding and utilizing sterile lines with a higher SER would be a promising solution to cost-effective hybrid wheat seed production. [ABSTRACT FROM AUTHOR]

The information collected through multi-environment testing of wheat genotypes not only provides basis to identify promising genotypes but also to ascertain their yield potential and the genetic gains. For this purpose, in the presented study, the data originated from the Yunnan provincial Regional Yield Trials (RYT) conducted during 2006 and 2018 was used. During this period, 107 genotypes were evaluated at 18 locations under Upland Wheat (UW) management scheme, while 116 genotypes were evaluated at 21 locations under Field Wheat (FW) management scheme. By adopting standard statistical approaches and through repeated elimination procedures, 7 genotypes emerged as promising for UW and 11 for FW cultivation. These genotypes have genetic variance >1 and 44/33% higher average yield than that of UW/FW genotypes. Most of these promising genotypes were tested during 2016 and 2018 cropping seasons. This indicated a good genetic gain of around 0.7 t/ha in recent years from that of base year. These genotypes, however, needs to be further evaluated in diverse environments suitable for spring type wheat cultivation to ascertain the extent of their interaction with wider environmental conditions and possibility of using in local breeding programs of those target environments.

Based on the finite element thought and optimization design method,the research of lightweight on the 12 meter bus body frame of a manufacturer had been made. By establishing finite element model of the body frame,horizontal bending and torsion limit of it had been simulated. Through free modal of bus body frame simulated,static and dynamic characteristics of frame had been analyzed. Taking first order bending,torsion frequency of the frame,bending and torsional flexibility as constraint conditions and the minimum volume as the objective function,to analysis topology optimization of it. That based on the results of topology optimization,selecting 371 groups of bars as design variables to have sensitivity analysis for the frame. According to the result of topology optimization and sensitivity analysis,combining the regulation of company for finalize the design product,lightweight of body frame has been put forward,which made skeleton quality reduced by 240 kg. Compared with original frame,vibration characteristics of the new one have been maintained,and strength improved significantly. Achieving lightweight goal of the bus body frame.