Search

Search Results

• 1. [Article] Nature of inheritance and association of time, duration and rate of grain filling and subsequent grain yield in crosses of winter and spring wheats (Triticum aestivum L. em Thell)

  The nature of inheritance and possible associations for traits influencing earliness and grain yield were investigated using a four parent diallel of winter and spring wheat cultivars. More genetic variability ...

  Citation × Citation Citation Abstract Copy Title: Nature of inheritance and association of time, duration and rate of grain filling and subsequent grain yield in crosses of winter and spring wheats (Triticum aestivum L. em Thell) Author: Choi, Byung Han The nature of inheritance and possible associations for traits influencing earliness and grain yield were investigated using a four parent diallel of winter and spring wheat cultivars. More genetic variability was observed for the traits measured in segregating populations resulting from crosses between winter and spring type wheats in contrast to spring x spring or winter x winter crosses. The one exception was plant height where more genetic variability resulted from spring x spring crosses. Narrow sense heritability estimates were high for time and duration of heading, anthesis, grain filling and physiological maturity and for plant height. Smaller values were noted for rate of grain filling, kernel number, harvest index, tiller number, kernel weight, whole plant dry weight and grain yield. Estimates of the coefficient of heritability and the parent-offspring correlation coefficient were similar in magnitude except for the traits grain yield, tiller number, kernel weight and whole plant dry weight where large variations due to the environment were encountered. Using the Jinks-Hayman model, no maternal effects were noted nor were any nonallelic interactions observed for total duration of grain filling and lag period. The actual grain filling period was influenced to some degree by such interactions. The spring cultivars also appeared to have more dominant genes for longer total duration of grain filling and lag period. In contrast the winter parents had more dominant genes for the longer actual grain filling period. Estimates of general and specific combining ability provided similar evidence in terms of the nature of gene action. Both additive and nonadditive gene action was present for all traits, the relative magnitudes depending on the specific trait. Based on individual combining ability effects, the winter x spring cross Yamhill x Siete Cerros would appear to provide the highest proportion of desired segregates when combining earliness and acceptable grain yield. From the direct and indirect associations of grain yield, it would appear that a shorter duration of grain filling along with a shorter lag period from heading to anthesis are important for higher rates of grain filling if negative associations between earliness and grain yield are to be avoided. Title: Nature of inheritance and association of time, duration and rate of grain filling and subsequent grain yield in crosses of winter and spring wheats (Triticum aestivum L. em Thell) Author: Choi, Byung Han The nature of inheritance and possible associations for traits influencing earliness and grain yield were investigated using a four parent diallel of winter and spring wheat cultivars. More genetic variability was observed for the traits measured in segregating populations resulting from crosses between winter and spring type wheats in contrast to spring x spring or winter x winter crosses. The one exception was plant height where more genetic variability resulted from spring x spring crosses. Narrow sense heritability estimates were high for time and duration of heading, anthesis, grain filling and physiological maturity and for plant height. Smaller values were noted for rate of grain filling, kernel number, harvest index, tiller number, kernel weight, whole plant dry weight and grain yield. Estimates of the coefficient of heritability and the parent-offspring correlation coefficient were similar in magnitude except for the traits grain yield, tiller number, kernel weight and whole plant dry weight where large variations due to the environment were encountered. Using the Jinks-Hayman model, no maternal effects were noted nor were any nonallelic interactions observed for total duration of grain filling and lag period. The actual grain filling period was influenced to some degree by such interactions. The spring cultivars also appeared to have more dominant genes for longer total duration of grain filling and lag period. In contrast the winter parents had more dominant genes for the longer actual grain filling period. Estimates of general and specific combining ability provided similar evidence in terms of the nature of gene action. Both additive and nonadditive gene action was present for all traits, the relative magnitudes depending on the specific trait. Based on individual combining ability effects, the winter x spring cross Yamhill x Siete Cerros would appear to provide the highest proportion of desired segregates when combining earliness and acceptable grain yield. From the direct and indirect associations of grain yield, it would appear that a shorter duration of grain filling along with a shorter lag period from heading to anthesis are important for higher rates of grain filling if negative associations between earliness and grain yield are to be avoided. Close

• 2. [Article] Time and duration of growth stages and subsequent grain yield in selected wheat cultivars (Triticum aestivum L. em Thell)

  The need to develop a shorter life cycle wheat cultivar which would be more adapted to multiple cropping systems prompted this study. Thus the following information was obtained. Greatest variations in ...

  Citation × Citation Citation Abstract Copy Title: Time and duration of growth stages and subsequent grain yield in selected wheat cultivars (Triticum aestivum L. em Thell) Author: Choi, Byung Han The need to develop a shorter life cycle wheat cultivar which would be more adapted to multiple cropping systems prompted this study. Thus the following information was obtained. Greatest variations in developmental patterns were found in the stem elongation, booting, inflorescence emergence and anthesis for five winter and five spring cultivars when planted at different dates. Differences among the ten winter wheat cultivars in time, duration and rate of grain filling was also observed. Generally later flowering cultivars had a more rapid rate of grain filling than early flowering cultivars with the net result being that physiological maturity was similar between the two groups. Actual grain filling period from flowering to physiological maturity varied among the cultivars, but larger differences were observed in lag period from heading to flowering. The duration of lag period contributed to the largest difference in total grain filling period from heading to physiological maturity. Changes in visual spike color of the glumes and main axis of a spike was satisfactory in identifying physiological maturity without destruction of the spike; however changes in kernel color was a more direct and precise method. Physiological maturity is a better measure of the optimum harvesting time to provide for maximum grain yield for planting sequential crops. Grain yield was positively associated with time of heading, flowering, physiological maturity, rate of grain filling and components of grain yield, but negatively associated with duration of grain filling period, lag period and harvest index. There was little association with the duration of the actual grain filling period and grain yield. However, a large association was observed between grain yield and the rate of grain filling. The direct effects of tiller number and rate of grain filling on grain yield were consistently positive and high. The indirect effects of rate of grain filling on grain yield were positive and high via time of heading, flowering and physiological maturity, components of yield and whole plant dry weight, but negative and high via duration of grain filling period, lag period and harvest index. Title: Time and duration of growth stages and subsequent grain yield in selected wheat cultivars (Triticum aestivum L. em Thell) Author: Choi, Byung Han The need to develop a shorter life cycle wheat cultivar which would be more adapted to multiple cropping systems prompted this study. Thus the following information was obtained. Greatest variations in developmental patterns were found in the stem elongation, booting, inflorescence emergence and anthesis for five winter and five spring cultivars when planted at different dates. Differences among the ten winter wheat cultivars in time, duration and rate of grain filling was also observed. Generally later flowering cultivars had a more rapid rate of grain filling than early flowering cultivars with the net result being that physiological maturity was similar between the two groups. Actual grain filling period from flowering to physiological maturity varied among the cultivars, but larger differences were observed in lag period from heading to flowering. The duration of lag period contributed to the largest difference in total grain filling period from heading to physiological maturity. Changes in visual spike color of the glumes and main axis of a spike was satisfactory in identifying physiological maturity without destruction of the spike; however changes in kernel color was a more direct and precise method. Physiological maturity is a better measure of the optimum harvesting time to provide for maximum grain yield for planting sequential crops. Grain yield was positively associated with time of heading, flowering, physiological maturity, rate of grain filling and components of grain yield, but negatively associated with duration of grain filling period, lag period and harvest index. There was little association with the duration of the actual grain filling period and grain yield. However, a large association was observed between grain yield and the rate of grain filling. The direct effects of tiller number and rate of grain filling on grain yield were consistently positive and high. The indirect effects of rate of grain filling on grain yield were positive and high via time of heading, flowering and physiological maturity, components of yield and whole plant dry weight, but negative and high via duration of grain filling period, lag period and harvest index. Close