Dry weight and nitrogen content of leaves, stems, kernels, and roots were determined for five spring wheat varieties on seven dates. Maximum leaf development occurred by July 19 (flowering), and maximum stem development ocurred by July 29 (filling). By August 19 (maturity) the top weights were similar for all varieties except ‘Mindum’, which was significantly higher. The average ratio of root (to 5‐ft depth) to top growth on August 19 was 1:14.9. Uptake of nitrogen continued until harvest, although the rate was much slower after July 19. Nitrogen content in the roots was low at all sampling dates, indicating rapid translocation to aboveground parts. If all root nitrogen had been translocated to the kernels, the effect on kernel nitrogen would have been insignificant. The average ratio of root to top nitrogen on August 19 was 1:23.4. The r value of 0.95 between pounds of kernel nitrogen and pounds of top dry weight indicates that 90.2% of the variation in kernel nitrogen in this experiment is due to differences in plant dry weight. This leaves only 9.8% of the variation in kernel nitrogen which the plant breeder might be able to manipulate. We suggest that if wheat varieties which will translocate as much as 70% or more of leaf and stem nitrogen to the kernels can be found, they might be useful in breeding programs.

No abstract

We have investigated the relative pollen‐shedding abilities of 11 hard red spring and 3 durum wheat varieties and the relationships between pollen‐shedding and other varietal characteristics.The varieties differed in amount of pollen shed, number of pollen grains/anther, percent anthers extruded, tillers/plot, fertile florets/plot, fertile florets/tiller, yield, and kernel weight. Anther extrusion varied from 72% for ‘Thatcher’ spring wheat to 22% for ‘Lakota’ durum wheat. Number of pollen grains/anther varied from 3,867 for ‘Rescue’ to 2,687 for ‘Fortuna’ spring wheat.The amount of pollen shed was positively correlated with percent anthers extruded and tillers/plot but negatively correlated with fertile florets/tiller. Path coefficient analysis indicated that percent anther extrusion had the largest direct effect on pollen shedding. Pollen shedding ability of a variety was predicted on the basis of percent anther extrusion, pollen grains/anther and fertile florets/plot.

Five spring wheat (Triticum aestivum L.) varieties were fertilized with five N treatments in 1969 and two N treatments in 1970 near Belgrade, Mont. The varieties were chosen to represent short, medium, and tall height levels, and each was evaluated for agronomic and quality response. Grain yields of normal ‘Centana’ and medium Centana were similar, even though medium Centana was 25% shorter and the straw yield was 17% less. There was no variety‐by‐fertilizer interaction for yield, indicating that the short and medium height types did not respond any better to N fertilizer than the standard height types. Short Centana had significantly less of its protein translocated from plant to grain than tall or medium Centana. Gain protein percentages decreased as the grainstraw ratio increased, suggesting that the amount of top growth is important in extracting nutrients from the soil. Nitrogen fertilizer significantly increased grain protein percentages, and there was a corresponding increase in loaf volume and grain and texture scores. Baking absorption and mixing time decreased slightly with increasing amounts of N. Water use was similar for the five varieties and increased with increasing rates of N.

No abstract

No abstract

Samples of high and low grain protein content (%) were compared from each of eight spring wheat crosses. The high protein samples were obtained by compositing 14 F3 progeny rows from the high end of the F3 distribution curve; the low protein samples were obtained similarly from the low end of the F3 distribution curve. These composites were seeded at three Montana locations and evaluated for agronomicharacteristics and for grain and plant nitrogen to help determine the nature of the expression of grain nitrogen content in spring wheat.Grain nitrogen content was negatively related to grain yield and to the graln‐straw ratio. High and low protein composites at Bozeman produced the same amount of above ground plant nitrogen, and each translocated the same percent of nitrogen to grain. However, grain nitrogen content of the high protein composite was significantly higher because of the distribution of a similar amount of nitrogen to a smaller amount of grain.Differences in plant growth characteristics among the eight crosses seem to account for the differences in grain nitrogen content.

Microgametogenesis was compared in anthers of fertile and cytoplasmic male sterile winter wheat. Tapetal cells formed less starch and persisted longer in male sterile than in fertile anthers. Meiosis in pollen mother cells of sterile anthers was normal, but little or no starch was observed in the mature pollen. We suggest that male sterility in wheat may be caused by vascular deficiencies in the stamen.