Italian ryegrass is an annual/biennial grass that is typically used as a pasture crop or a cover crop along roadsides, rights-of-way, and industrial areas. Glyphosate-resistant (GR) Italian ryegrass populations have b...Italian ryegrass is an annual/biennial grass that is typically used as a pasture crop or a cover crop along roadsides, rights-of-way, and industrial areas. Glyphosate-resistant (GR) Italian ryegrass populations have been documented around the world, mostly in orchard and vineyard situations. The first evidence of evolved GR Italian ryegrass in row/agronomic crops was reported from Washington County, Mississippi in 2005. GR Italian ryegrass populations can jeopardize preplant burndown options in reduced-tillage crop production systems, thereby, delaying planting operations. The effects of competition of Italian ryegrass on crop growth and yield are poorly understood. A field study was conducted in the 2012 growing season and repeated in the 2013 growing season. GR and susceptible (GS) Italian ryegrass populations were established in the greenhouse and transplanted in prepared corn row beds in the fall of 2011 and 2012 at 0, 1, 2, 3, and 4 plants·meter> of crop row. Italian ryegrass plants overwintered and developed over the following spring-summer. Glyphosate was applied at 1.26 kg·ae/ha (1.5× of labeled rate) in the spring to burndown the Italian ryegrass plants and corn was planted into the ryegrass residue 2 - 3 wk later. Current corn production practices were followed. Corn density (early and late season), height (early season), and yield and Italian ryegrass biomass (early-mid season) measurements were recorded during both years. Corn height was greater in 2012 than that in 2013 at comparable stages of the growing season, due to a cooler and wetter early season in 2013 than that in 2012. Averaged across weed densities, corn density (both early and late season) and yield were higher in the GS than those in the GR population, but Italian ryegrass biomass was similar for both populations. Averaged across Italian ryegrass populations, corn density (both early and late season), and yield were inversely proportional to Italian ryegrass density. In summary, Italian ryegrass significantly reduced corn density and yield and reduction was greater with the GR than that with the GS population. Studies are underway to study inter population competition in Italian ryegrass and investigate allelopathic effects of Italian ryegrass on selected crops.展开更多
A greenhouse pot experiment was conducted using a complete random design with six replications. A pressure-volume curve analysis was employed to study the effects of organic fertilizers on plant water relations in swe...A greenhouse pot experiment was conducted using a complete random design with six replications. A pressure-volume curve analysis was employed to study the effects of organic fertilizers on plant water relations in sweet corn (Zea mays L. cv. Honey-bantam) in terms of leaf osmotic concentration (Cs), osmotic potentials at full turgid status (πFT) and at incipient plasmolysis (πIP), and of symplastic (ζsym) and apoplastic (ζapo) fractions in the tissue water compartment in relation to photosynthetic capacity (Pc) and dry mass accumulation. At the seedling stage (day 15), plants with chemical fertilizer treatments showed lower πFT, πIP and ζapo and higher Cs, ζsym and PC than those with organic fertilizer treatments. Compared to PC and relative growth, where values from day 15 to day 75 were first lower for organic treatments and then higher, ζsym and Cs values were similar, while πFT and πIP were opposite being higher then lower. Dry mass production with organic fertilizer was higher than or close to the chemical fertilizer treatments in the later growth stage (day 75), though dry mass production with chemical fertilizers was much higher in the early and middle growing stages (days 15 and 45). Increased photosynthesis and dry mass production in later growth stages due to organic fertilizers were associated with increased osmotic concentration in the tissue and the symplastic fraction of the tissue water compartment. These might favor stomatal opening and biochemical activities.展开更多
The abortive behaviour and the cytoplasm quality of cytoplasmic male-sterility(CMS)lines of homocaryon were investigated and the existence of C race of Bipolaris maydiswere discussed from the point of view of genetic ...The abortive behaviour and the cytoplasm quality of cytoplasmic male-sterility(CMS)lines of homocaryon were investigated and the existence of C race of Bipolaris maydiswere discussed from the point of view of genetic breeding,physiology and pathology in this paper.Then the countermeasures to prevent the danger from disease of B. maydis in CMS hybrid pro-duction were proposed.展开更多
为了进行鲜食型糯玉米(Zea mays L. sinensis Kulesh)种质资源的创新、改良加工品质、选育优质高产的新品种。本试验以7个糯玉米自交系为亲本,按照GriffingⅣ配制21个杂交组合,分析了糯玉米产量和出籽率的配合力效应。结果表明,糯玉米...为了进行鲜食型糯玉米(Zea mays L. sinensis Kulesh)种质资源的创新、改良加工品质、选育优质高产的新品种。本试验以7个糯玉米自交系为亲本,按照GriffingⅣ配制21个杂交组合,分析了糯玉米产量和出籽率的配合力效应。结果表明,糯玉米的产量和出籽率受加性基因和非加性基因共同控制;7个亲本的产量一般配合力效应大小顺序为N23>N17>N28>N47>N51>N15>N27,出籽率一般配合力效应大小值为N51>N27>N47>N23>N28>N17>N15;综合一般配合力效应及特殊配合力效应结果表明,N15×N23是相对高产的组合;N27×N51是出籽率相对较高的组合;对自交系综合评价表明,N23、N17可作为选育高产优良组合的理想亲本,N27可作为选育高出籽率的理想亲本。本研究结果可为糯玉米育种实践提供一定的参考。展开更多
The sugar components and their dynamic variation in the developing grains of sweet corn(Zea mays L. seccharata Sturt)and normal corn (Zea mays L. indentata Sturt) were compared. There are WSP (water-soluble polysaccha...The sugar components and their dynamic variation in the developing grains of sweet corn(Zea mays L. seccharata Sturt)and normal corn (Zea mays L. indentata Sturt) were compared. There are WSP (water-soluble polysaccharides), sucrose, fructose, glucose, mannitol and sorbitol in both sweet corn and normal corn, but no maltose. Two components with different degrees of polymerization (D. P. N) were detected in the sweet corn; only one of them was detected in the normal corn 20 days after pollination. With the development of grains, the total soluble sugar content(TSS)in sweet corn increased, but in normal corn it decreased. The dynamic variation of WSP, sucrose, glucose, fructose, mannitol and sorbitol in sweet and normal corn grains are different. The contents of sugar components in the sweet corn grains are higher than that in the normal corn. Sweet corn accumulates less starch than normal corn.展开更多
Eleven field trials were conducted over a three-year period (2006-2008) at three locations in southwestern Ontario, Canada to evaluate the effect of various weed management strategies in glyphosate-tolerant corn on we...Eleven field trials were conducted over a three-year period (2006-2008) at three locations in southwestern Ontario, Canada to evaluate the effect of various weed management strategies in glyphosate-tolerant corn on weed control, crop injury, corn yield, environmental impact and profit margin. No visible injury resulted from the herbicide treatments evaluated. Overall, the effect of all factors assessed were location specific. By 56 days after treatment, depending on location, glyphosate applied at the 7 - 8 leaf stage (LPOST), preemergence (PRE) herbicides followed by (fb) glyphosate LPOST and sequential glyphosate applications (EPOST (3 - 4 leaf stage) followed by LPOST) provided more consistent control of annual broadleaf weeds and annual grasses compared to glyphosate applied alone EPOST. Weed control at 56 days after treatment was lower when glyphosate was applied alone LPOST compared to sequential applications of glyphosate or PRE herbicides fb glyphosate. There were no differences in corn yield among the sequential programs evaluated;however, a yield benefit was found when a sequential program was used compared to glyphosate applied alone LPOST. Among the sequential programs the lowest environmental impact was isoxaflutole/atrazine fb glyphosate. The lowest profit margins were associated with atrazine, S-metolachlor/atrazine/benoxacor, dicamba/atrazine and glyphosate LPOST treatments compared to all other treatments. Overall, profit margins tended to be somewhat higher for treatments that included glyphosate applications. Based on these results, the most efficacious and profitable weed management program in corn was a sequential application of glyphosate;however, isoxaflutole/atrazine fb glyphosate was the treatment with the lowest environmental risk while also adding glyphosate stewardship benefits.展开更多
Nine field trials (4 in corn and 5 in soybean) were conducted over 2 years (2014 and 2015) to determine if there is greater benefit of adding ammonium sulfate (AMS) (2.5 L·ha<sup>ˉ1</sup>) or an equa...Nine field trials (4 in corn and 5 in soybean) were conducted over 2 years (2014 and 2015) to determine if there is greater benefit of adding ammonium sulfate (AMS) (2.5 L·ha<sup>ˉ1</sup>) or an equal dollar value of glyphosate (406 g·ae·ha<sup>ˉ1</sup>) to glyphosate applied at 450, 675 or 900 g·ae·ha<sup>ˉ1</sup> for weed control in corn and soybean. Glyphosate applied at 450 g·ae·ha<sup>ˉ1</sup> controlled velvetleaf 90% to 98%, common ragweed 80% - 97%, common lambsquarters 91% - 99%, Eastern black nightshade 83% - 100% and barnyardgrass 73% - 97% in corn and common ragweed 37% - 89%, common lambsquarters 39% - 98%, barnyardgrass 90% - 98% and green foxtail 91% - 98% in soybean. The addition of AMS to glyphosate applied at 450, 675 or 900 g·ae·ha<sup>ˉ1</sup> provided little to no added benefit for the control of velvetleaf, common ragweed, common lambsquarters, Eastern black nightshade, barnyardgrass and green foxtail in corn and soybean. There was a greater benefit in weed control efficacy by simply adding and equal dollar value of glyphosate (406 g·ae·ha<sup>ˉ1</sup>) than AMS (2.5 L·ha<sup>ˉ1</sup>) to glyphosate. There was no difference in corn or soybean yield among the herbicide treatments evaluated. Based on these results, addition of AMS to glyphosate at rates evaluated had little benefit on weed control efficacy or yield of corn and soybean.展开更多
文摘Italian ryegrass is an annual/biennial grass that is typically used as a pasture crop or a cover crop along roadsides, rights-of-way, and industrial areas. Glyphosate-resistant (GR) Italian ryegrass populations have been documented around the world, mostly in orchard and vineyard situations. The first evidence of evolved GR Italian ryegrass in row/agronomic crops was reported from Washington County, Mississippi in 2005. GR Italian ryegrass populations can jeopardize preplant burndown options in reduced-tillage crop production systems, thereby, delaying planting operations. The effects of competition of Italian ryegrass on crop growth and yield are poorly understood. A field study was conducted in the 2012 growing season and repeated in the 2013 growing season. GR and susceptible (GS) Italian ryegrass populations were established in the greenhouse and transplanted in prepared corn row beds in the fall of 2011 and 2012 at 0, 1, 2, 3, and 4 plants·meter> of crop row. Italian ryegrass plants overwintered and developed over the following spring-summer. Glyphosate was applied at 1.26 kg·ae/ha (1.5× of labeled rate) in the spring to burndown the Italian ryegrass plants and corn was planted into the ryegrass residue 2 - 3 wk later. Current corn production practices were followed. Corn density (early and late season), height (early season), and yield and Italian ryegrass biomass (early-mid season) measurements were recorded during both years. Corn height was greater in 2012 than that in 2013 at comparable stages of the growing season, due to a cooler and wetter early season in 2013 than that in 2012. Averaged across weed densities, corn density (both early and late season) and yield were higher in the GS than those in the GR population, but Italian ryegrass biomass was similar for both populations. Averaged across Italian ryegrass populations, corn density (both early and late season), and yield were inversely proportional to Italian ryegrass density. In summary, Italian ryegrass significantly reduced corn density and yield and reduction was greater with the GR than that with the GS population. Studies are underway to study inter population competition in Italian ryegrass and investigate allelopathic effects of Italian ryegrass on selected crops.
文摘A greenhouse pot experiment was conducted using a complete random design with six replications. A pressure-volume curve analysis was employed to study the effects of organic fertilizers on plant water relations in sweet corn (Zea mays L. cv. Honey-bantam) in terms of leaf osmotic concentration (Cs), osmotic potentials at full turgid status (πFT) and at incipient plasmolysis (πIP), and of symplastic (ζsym) and apoplastic (ζapo) fractions in the tissue water compartment in relation to photosynthetic capacity (Pc) and dry mass accumulation. At the seedling stage (day 15), plants with chemical fertilizer treatments showed lower πFT, πIP and ζapo and higher Cs, ζsym and PC than those with organic fertilizer treatments. Compared to PC and relative growth, where values from day 15 to day 75 were first lower for organic treatments and then higher, ζsym and Cs values were similar, while πFT and πIP were opposite being higher then lower. Dry mass production with organic fertilizer was higher than or close to the chemical fertilizer treatments in the later growth stage (day 75), though dry mass production with chemical fertilizers was much higher in the early and middle growing stages (days 15 and 45). Increased photosynthesis and dry mass production in later growth stages due to organic fertilizers were associated with increased osmotic concentration in the tissue and the symplastic fraction of the tissue water compartment. These might favor stomatal opening and biochemical activities.
文摘The abortive behaviour and the cytoplasm quality of cytoplasmic male-sterility(CMS)lines of homocaryon were investigated and the existence of C race of Bipolaris maydiswere discussed from the point of view of genetic breeding,physiology and pathology in this paper.Then the countermeasures to prevent the danger from disease of B. maydis in CMS hybrid pro-duction were proposed.
文摘为了进行鲜食型糯玉米(Zea mays L. sinensis Kulesh)种质资源的创新、改良加工品质、选育优质高产的新品种。本试验以7个糯玉米自交系为亲本,按照GriffingⅣ配制21个杂交组合,分析了糯玉米产量和出籽率的配合力效应。结果表明,糯玉米的产量和出籽率受加性基因和非加性基因共同控制;7个亲本的产量一般配合力效应大小顺序为N23>N17>N28>N47>N51>N15>N27,出籽率一般配合力效应大小值为N51>N27>N47>N23>N28>N17>N15;综合一般配合力效应及特殊配合力效应结果表明,N15×N23是相对高产的组合;N27×N51是出籽率相对较高的组合;对自交系综合评价表明,N23、N17可作为选育高产优良组合的理想亲本,N27可作为选育高出籽率的理想亲本。本研究结果可为糯玉米育种实践提供一定的参考。
文摘The sugar components and their dynamic variation in the developing grains of sweet corn(Zea mays L. seccharata Sturt)and normal corn (Zea mays L. indentata Sturt) were compared. There are WSP (water-soluble polysaccharides), sucrose, fructose, glucose, mannitol and sorbitol in both sweet corn and normal corn, but no maltose. Two components with different degrees of polymerization (D. P. N) were detected in the sweet corn; only one of them was detected in the normal corn 20 days after pollination. With the development of grains, the total soluble sugar content(TSS)in sweet corn increased, but in normal corn it decreased. The dynamic variation of WSP, sucrose, glucose, fructose, mannitol and sorbitol in sweet and normal corn grains are different. The contents of sugar components in the sweet corn grains are higher than that in the normal corn. Sweet corn accumulates less starch than normal corn.
文摘Eleven field trials were conducted over a three-year period (2006-2008) at three locations in southwestern Ontario, Canada to evaluate the effect of various weed management strategies in glyphosate-tolerant corn on weed control, crop injury, corn yield, environmental impact and profit margin. No visible injury resulted from the herbicide treatments evaluated. Overall, the effect of all factors assessed were location specific. By 56 days after treatment, depending on location, glyphosate applied at the 7 - 8 leaf stage (LPOST), preemergence (PRE) herbicides followed by (fb) glyphosate LPOST and sequential glyphosate applications (EPOST (3 - 4 leaf stage) followed by LPOST) provided more consistent control of annual broadleaf weeds and annual grasses compared to glyphosate applied alone EPOST. Weed control at 56 days after treatment was lower when glyphosate was applied alone LPOST compared to sequential applications of glyphosate or PRE herbicides fb glyphosate. There were no differences in corn yield among the sequential programs evaluated;however, a yield benefit was found when a sequential program was used compared to glyphosate applied alone LPOST. Among the sequential programs the lowest environmental impact was isoxaflutole/atrazine fb glyphosate. The lowest profit margins were associated with atrazine, S-metolachlor/atrazine/benoxacor, dicamba/atrazine and glyphosate LPOST treatments compared to all other treatments. Overall, profit margins tended to be somewhat higher for treatments that included glyphosate applications. Based on these results, the most efficacious and profitable weed management program in corn was a sequential application of glyphosate;however, isoxaflutole/atrazine fb glyphosate was the treatment with the lowest environmental risk while also adding glyphosate stewardship benefits.
文摘Nine field trials (4 in corn and 5 in soybean) were conducted over 2 years (2014 and 2015) to determine if there is greater benefit of adding ammonium sulfate (AMS) (2.5 L·ha<sup>ˉ1</sup>) or an equal dollar value of glyphosate (406 g·ae·ha<sup>ˉ1</sup>) to glyphosate applied at 450, 675 or 900 g·ae·ha<sup>ˉ1</sup> for weed control in corn and soybean. Glyphosate applied at 450 g·ae·ha<sup>ˉ1</sup> controlled velvetleaf 90% to 98%, common ragweed 80% - 97%, common lambsquarters 91% - 99%, Eastern black nightshade 83% - 100% and barnyardgrass 73% - 97% in corn and common ragweed 37% - 89%, common lambsquarters 39% - 98%, barnyardgrass 90% - 98% and green foxtail 91% - 98% in soybean. The addition of AMS to glyphosate applied at 450, 675 or 900 g·ae·ha<sup>ˉ1</sup> provided little to no added benefit for the control of velvetleaf, common ragweed, common lambsquarters, Eastern black nightshade, barnyardgrass and green foxtail in corn and soybean. There was a greater benefit in weed control efficacy by simply adding and equal dollar value of glyphosate (406 g·ae·ha<sup>ˉ1</sup>) than AMS (2.5 L·ha<sup>ˉ1</sup>) to glyphosate. There was no difference in corn or soybean yield among the herbicide treatments evaluated. Based on these results, addition of AMS to glyphosate at rates evaluated had little benefit on weed control efficacy or yield of corn and soybean.
