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.
| Food security is of growing concern around the globe. Wheat, being one of the staple food commodities, is of utmost importance for millions. However, its productivity is determined by various genotypic, environmental and crop management factors. In this study, we elaborated the role of these factors, in rainfed agro-ecology, using data of six genotypes, grown in four sowing windows over six years. The rainfed wheat productivity is predominantly determined by environmental conditions, particularly rainfall induced moisture availability. Hence, the best match between sowing time and the environment prevailed at that time emerged as an important yield determining factor. Overall, grain yield varied between 2.5-4.9 t/ha in these genotypes, between 2.7-4.8 t/h over years and between 2.0-5.1 t/ha across sowing windows. Therefore, greater variation was observed with change in sowing time followed by genotypes. This management strategy holds for up to 67% variations in grain yield and other crop growth and development related parameters. These results highlighted the necessity to have genotypic diversity for best exploitation of the environmental conditions coupled with appropriate crop management strategy. The best match of this genotype × environment × management production paradigm could lead to sustained improvement in wheat grain yield.
This study was conducted to identify desirable wheat germplasm for superior hybrid cross combinations through 1) identifying the best parents with high combining ability (CA) and 2) estimating heterosis effects. Two thermophoto-sensitive-genic-male-sterile lines (K456s and K78s) as female parents and 60 restorer lines as males were crossed according to line × tester hybridization method. The observed variation for most of the nine studied characters and <1 ratio for general (G)/specific (S) CA suggested governance of non-additive gene action. The GCA for K456s was higher than K78s in six out of nine characters, while restorers 2016Y2-2776 and 2016Y2-4117 had the highest in five characters. The crosses K78s/R31 and K456s/R2 had highest positive SCA values in five and six characters, respectively. The crosses K78s/R43 and K456s/R21 had the overall highest significant positive heterosis estimates for the best cross with respect to yield plant-1 and has the potential for utilization in hybrid wheat breeding program.
S IX selected bread wheat double haploid genotypes with same heading time and different genetic background and eight maize genotypes belonging to four maize types (waxy, sweet waxy, sweet and super sweet maize types) were used in this study. The six wheat genotypes pollinated with the eight maize genotypes to produce wheat haploid embryos. The objective of this investigation was to study the effects of different maize genotypes of distinct types on the wheat haploid embryo ratio. The results showed that the same wheat material when pollinated with different maize genotype, the embryo rate differed between 1.5 to 3 times and ranging from 15.43% to 47.80%. Screening high induction rate maize varieties was essential to improve the efficiency of wheat haploid production. The average haploid embryo induction rate among the four maize types was highest in sweet type (33.24%) and lowest in super sweet type (29.59%). The wheat genotype A6 recorded the highest embryo rate percentage (34.11%), while A5 recorded the lowest rate (29.36%). Baitiannuo SQW-1 (B4) found to be the highest for embryo rate, followed by the Yuntianyu 6 (B5) and Zhenhenuo 1(B1), while the lowest was recorded by Yunchaotian 2 (B8) genotype. The maize genotypes in the same type differed significantly regarding the haploid embryo induction rate of wheat genotypes and thus maize types were not consistent in their behavior. So, the key was to select maize genotypes with high induction rate for wheat haploids and not the maize type. The interaction between wheat genotype and maize genotype has a significant effect on the embryogenesis rate. Therefore, if the rate of embryo induction of some wheat materials with a common maize variety is low, it may be possible using the pollination of other maize genotypes to increase the embryogenesis in wheat x maize hybridization.
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