Grasslands account for almost one quarter of the world’s cover of vegetation. Almost three quarter of the world’s milk, beef and veal are produced from temperate grasslands. In New Zealand, ryegrass (Lolium perenne) is the main pasture constituent with more than half of the total export revenue coming from grass-related products. Much of ryegrass production and quality depends on the timing of flowering through seasonal progression. In many plants, day length is the critical environmental parameter that controls when plants begin to flower. In Arabidopsis the CONSTANS (CO) gene mediates day length response. Upstream of CO is the GIGANTEA (GI) gene which is associated with the circadian clock mechanism and is required to promote CO expression. The FT gene is the immediate downstream genetic target of CO and is a direct promoter of flowering. In this study, cDNA libraries, sequence alignment and genome walking were used to sequence and describe three putative orthologues from the ryegrass photoperiod pathway: LpGI, LpCOL1, and LpFT3. All three behaved in a true photoperiod manner characterised by cycling expression patterns under continuous light conditions and differential expression patterns in LD and SD conditions. Different photoperiods brought about differences in expression of these genes measured either by the phase shift change (LpGI and LpCOL1) or by the change of the transcript level (LpFT3). Gene expression changes over a vernalisaton time course were also analysed and results indicated that LpFT3 acts as the flowering integrator. The role of LpGI, LpCOL1, and LpFT3 as putative photoperiod genes was further confirmed by genetic mapping, which placed them on linkage groups 3, 6, and 7, respectively. The syntenic positions in rice contain major heading date quantitative trait loci. The function of LpFT3 was examined by over-expressing the gene in Arabidopsis under control of the cauliflower mosiac virus (CaMV) 35S promoter. Substantially higher expression of the endogenous Arabidopsis AtFT transcript was observed in the mutated ft-1 line overexpressing LpFT3, suggesting a positive feedback loop either directly or through upstream intermediaries. Overexpression of the LpGI and LpFT3 genes restored rapid flowering to the respective gi-3 and ft-1 Arabidopsis mutants while overexpression of LpCOL1 did not accelerate flowering either in co-2 or wild type Arabidopsis plants. However, overexpression of LpCOL1 completely restored the late flowering phenotype of the gi-3 mutant indicating the existence of another important link outside the well established hierarchy of GI-CO-FT in the photoperiod pathway. This study revealed that the ryegrass photoperiod pathway genes show high similarity to their wheat, rice and Arabidopsis counterparts. Exploring ways to modulate flowering time in ryegrass could provide major benefits to the agricultural industry by increasing forage quality, controlling seed and pollen production, and addressing potential problems linked with climate change.

Grasslands account for almost one quarter of the world’s cover of vegetation. Almost three quarter of the world’s milk, beef and veal are produced from temperate grasslands. In New Zealand, ryegrass (Lolium perenne) is the main pasture constituent with more than half of the total export revenue coming from grass-related products. Much of ryegrass production and quality depends on the timing of flowering through seasonal progression. In many plants, day length is the critical environmental parameter that controls when plants begin to flower. In Arabidopsis the CONSTANS (CO) gene mediates day length response. Upstream of CO is the GIGANTEA (GI) gene which is associated with the circadian clock mechanism and is required to promote CO expression. The FT gene is the immediate downstream genetic target of CO and is a direct promoter of flowering. In this study, cDNA libraries, sequence alignment and genome walking were used to sequence and describe three putative orthologues from the ryegrass photoperiod pathway: LpGI, LpCOL1, and LpFT3. All three behaved in a true photoperiod manner characterised by cycling expression patterns under continuous light conditions and differential expression patterns in LD and SD conditions. Different photoperiods brought about differences in expression of these genes measured either by the phase shift change (LpGI and LpCOL1) or by the change of the transcript level (LpFT3). Gene expression changes over a vernalisaton time course were also analysed and results indicated that LpFT3 acts as the flowering integrator. The role of LpGI, LpCOL1, and LpFT3 as putative photoperiod genes was further confirmed by genetic mapping, which placed them on linkage groups 3, 6, and 7, respectively. The syntenic positions in rice contain major heading date quantitative trait loci. The function of LpFT3 was examined by over-expressing the gene in Arabidopsis under control of the cauliflower mosiac virus (CaMV) 35S promoter. Substantially higher expression of the endogenous Arabidopsis AtFT transcript was observed in the mutated ft-1 line overexpressing LpFT3, suggesting a positive feedback loop either directly or through upstream intermediaries. Overexpression of the LpGI and LpFT3 genes restored rapid flowering to the respective gi-3 and ft-1 Arabidopsis mutants while overexpression of LpCOL1 did not accelerate flowering either in co-2 or wild type Arabidopsis plants. However, overexpression of LpCOL1 completely restored the late flowering phenotype of the gi-3 mutant indicating the existence of another important link outside the well established hierarchy of GI-CO-FT in the photoperiod pathway. This study revealed that the ryegrass photoperiod pathway genes show high similarity to their wheat, rice and Arabidopsis counterparts. Exploring ways to modulate flowering time in ryegrass could provide major benefits to the agricultural industry by increasing forage quality, controlling seed and pollen production, and addressing potential problems linked with climate change.

Grasslands account for almost one quarter of the world’s cover of vegetation. Almost three quarter of the world’s milk, beef and veal are produced from temperate grasslands. In New Zealand, ryegrass (Lolium perenne) is the main pasture constituent with more than half of the total export revenue coming from grass-related products. Much of ryegrass production and quality depends on the timing of flowering through seasonal progression. In many plants, day length is the critical environmental parameter that controls when plants begin to flower. In Arabidopsis the CONSTANS (CO) gene mediates day length response. Upstream of CO is the GIGANTEA (GI) gene which is associated with the circadian clock mechanism and is required to promote CO expression. The FT gene is the immediate downstream genetic target of CO and is a direct promoter of flowering. In this study, cDNA libraries, sequence alignment and genome walking were used to sequence and describe three putative orthologues from the ryegrass photoperiod pathway: LpGI, LpCOL1, and LpFT3. All three behaved in a true photoperiod manner characterised by cycling expression patterns under continuous light conditions and differential expression patterns in LD and SD conditions. Different photoperiods brought about differences in expression of these genes measured either by the phase shift change (LpGI and LpCOL1) or by the change of the transcript level (LpFT3). Gene expression changes over a vernalisaton time course were also analysed and results indicated that LpFT3 acts as the flowering integrator. The role of LpGI, LpCOL1, and LpFT3 as putative photoperiod genes was further confirmed by genetic mapping, which placed them on linkage groups 3, 6, and 7, respectively. The syntenic positions in rice contain major heading date quantitative trait loci. The function of LpFT3 was examined by over-expressing the gene in Arabidopsis under control of the cauliflower mosiac virus (CaMV) 35S promoter. Substantially higher expression of the endogenous Arabidopsis AtFT transcript was observed in the mutated ft-1 line overexpressing LpFT3, suggesting a positive feedback loop either directly or through upstream intermediaries. Overexpression of the LpGI and LpFT3 genes restored rapid flowering to the respective gi-3 and ft-1 Arabidopsis mutants while overexpression of LpCOL1 did not accelerate flowering either in co-2 or wild type Arabidopsis plants. However, overexpression of LpCOL1 completely restored the late flowering phenotype of the gi-3 mutant indicating the existence of another important link outside the well established hierarchy of GI-CO-FT in the photoperiod pathway. This study revealed that the ryegrass photoperiod pathway genes show high similarity to their wheat, rice and Arabidopsis counterparts. Exploring ways to modulate flowering time in ryegrass could provide major benefits to the agricultural industry by increasing forage quality, controlling seed and pollen production, and addressing potential problems linked with climate change.

Grasslands account for almost one quarter of the world’s cover of vegetation. Almost three quarter of the world’s milk, beef and veal are produced from temperate grasslands. In New Zealand, ryegrass (Lolium perenne) is the main pasture constituent with more than half of the total export revenue coming from grass-related products. Much of ryegrass production and quality depends on the timing of flowering through seasonal progression. In many plants, day length is the critical environmental parameter that controls when plants begin to flower. In Arabidopsis the CONSTANS (CO) gene mediates day length response. Upstream of CO is the GIGANTEA (GI) gene which is associated with the circadian clock mechanism and is required to promote CO expression. The FT gene is the immediate downstream genetic target of CO and is a direct promoter of flowering. In this study, cDNA libraries, sequence alignment and genome walking were used to sequence and describe three putative orthologues from the ryegrass photoperiod pathway: LpGI, LpCOL1, and LpFT3. All three behaved in a true photoperiod manner characterised by cycling expression patterns under continuous light conditions and differential expression patterns in LD and SD conditions. Different photoperiods brought about differences in expression of these genes measured either by the phase shift change (LpGI and LpCOL1) or by the change of the transcript level (LpFT3). Gene expression changes over a vernalisaton time course were also analysed and results indicated that LpFT3 acts as the flowering integrator. The role of LpGI, LpCOL1, and LpFT3 as putative photoperiod genes was further confirmed by genetic mapping, which placed them on linkage groups 3, 6, and 7, respectively. The syntenic positions in rice contain major heading date quantitative trait loci. The function of LpFT3 was examined by over-expressing the gene in Arabidopsis under control of the cauliflower mosiac virus (CaMV) 35S promoter. Substantially higher expression of the endogenous Arabidopsis AtFT transcript was observed in the mutated ft-1 line overexpressing LpFT3, suggesting a positive feedback loop either directly or through upstream intermediaries. Overexpression of the LpGI and LpFT3 genes restored rapid flowering to the respective gi-3 and ft-1 Arabidopsis mutants while overexpression of LpCOL1 did not accelerate flowering either in co-2 or wild type Arabidopsis plants. However, overexpression of LpCOL1 completely restored the late flowering phenotype of the gi-3 mutant indicating the existence of another important link outside the well established hierarchy of GI-CO-FT in the photoperiod pathway. This study revealed that the ryegrass photoperiod pathway genes show high similarity to their wheat, rice and Arabidopsis counterparts. Exploring ways to modulate flowering time in ryegrass could provide major benefits to the agricultural industry by increasing forage quality, controlling seed and pollen production, and addressing potential problems linked with climate change.

Grasslands account for almost one quarter of the world’s cover of vegetation. Almost three quarter of the world’s milk, beef and veal are produced from temperate grasslands. In New Zealand, ryegrass (Lolium perenne) is the main pasture constituent with more than half of the total export revenue coming from grass-related products. Much of ryegrass production and quality depends on the timing of flowering through seasonal progression. In many plants, day length is the critical environmental parameter that controls when plants begin to flower. In Arabidopsis the CONSTANS (CO) gene mediates day length response. Upstream of CO is the GIGANTEA (GI) gene which is associated with the circadian clock mechanism and is required to promote CO expression. The FT gene is the immediate downstream genetic target of CO and is a direct promoter of flowering. In this study, cDNA libraries, sequence alignment and genome walking were used to sequence and describe three putative orthologues from the ryegrass photoperiod pathway: LpGI, LpCOL1, and LpFT3. All three behaved in a true photoperiod manner characterised by cycling expression patterns under continuous light conditions and differential expression patterns in LD and SD conditions. Different photoperiods brought about differences in expression of these genes measured either by the phase shift change (LpGI and LpCOL1) or by the change of the transcript level (LpFT3). Gene expression changes over a vernalisaton time course were also analysed and results indicated that LpFT3 acts as the flowering integrator. The role of LpGI, LpCOL1, and LpFT3 as putative photoperiod genes was further confirmed by genetic mapping, which placed them on linkage groups 3, 6, and 7, respectively. The syntenic positions in rice contain major heading date quantitative trait loci. The function of LpFT3 was examined by over-expressing the gene in Arabidopsis under control of the cauliflower mosiac virus (CaMV) 35S promoter. Substantially higher expression of the endogenous Arabidopsis AtFT transcript was observed in the mutated ft-1 line overexpressing LpFT3, suggesting a positive feedback loop either directly or through upstream intermediaries. Overexpression of the LpGI and LpFT3 genes restored rapid flowering to the respective gi-3 and ft-1 Arabidopsis mutants while overexpression of LpCOL1 did not accelerate flowering either in co-2 or wild type Arabidopsis plants. However, overexpression of LpCOL1 completely restored the late flowering phenotype of the gi-3 mutant indicating the existence of another important link outside the well established hierarchy of GI-CO-FT in the photoperiod pathway. This study revealed that the ryegrass photoperiod pathway genes show high similarity to their wheat, rice and Arabidopsis counterparts. Exploring ways to modulate flowering time in ryegrass could provide major benefits to the agricultural industry by increasing forage quality, controlling seed and pollen production, and addressing potential problems linked with climate change.

The objectives of this study were to evaluate nutrient digestibility and CP retention of steers fed ryegrass baleage supplemented with hay or soybean hull pellets. Crossbred steers (n=12, BW 247 plus or minus 20.8 kg) were halter broken, and placed into individual metabolism crates for a total of 10 days. All 12 steers had ad libitum access to ryegrass baleage and were allotted to 3 supplements 1) no supplement; 2) soybean hull pellets; 3) hay, with 4 steers per treatment group. Supplements were fed at 0.25% of steer body weight. Sample collections were for 7 days following a 3 day adaptation to crates. Results collected indicated there was no effect of supplementing a fiber source to cattle consuming ryegrass baleage on nutrient digestibility or CP retention. This may be attributed to maturity of ryegrass at harvest.

An in vitro continuous culture rumen fermentation experiment was conducted to evaluate digestibility of annual ryegrass either fed alone or annual ryegrass supplemented with hay, corn, or soybean hulls. Nutrient disappearance of feedstuffs offered were not different (P > 0.05) as a percentage of the diet however there were differences (P < 0.05) in amounts of individual nutrients digested for each treatment. Ammonia-N concentrations of culture samples were less (P < 0.05) for vessels fed corn as a supplement however there was no difference (P > 0.05) among vessels fed either ryegrass alone or supplemented with hay or soybean hulls. This may indicate a more efficient use of available nutrients from annual ryegrass when corn was supplemented.

Most professional turf in Virginia is comprised of bermudagrass (Cynodon dactylon L.) or (Cynodon dactylon x C. transvaalensis Burtt Davy) as a monoculture in summer and overseeded with perennial ryegrass (Lolium perenne L.) (PR) in winter, during bermudagrass dormancy. Two transitions are required in an overseeding program, fall establishment of PR and spring control of PR. During each transition, turf quality suffers as one grass dies or enters dormancy while another grass is promoted to fill voided areas. Field studies at various locations in Virginia were conducted to investigate methods of improving spring and fall transition. Bermudagrass green cover in August was influenced by duration of PR competition variably between three bermudagrass cultivars. For example, "Midiron", "Patriot", and "Riviera" bermudagrass required 218, 139, and 327 cumulative growing degree days at base 18.3 C (GDD) to reach 95% cover. Bermudagrass biomass was also positively correlated with increasing duration of noncompetitive GDD. Total nonstructural carbohydrates were not correlated to duration of PR competition. Novel application methods were invented and tested at Virginia Tech. Drip, sponge, and strip application methods were used to create patterns of PR control using selective herbicides. Controlling a portion of PR with these methods maintained acceptable turfgrass quality throughout the spring transition and improved bermudagrass cover 12 to 20%, speeding transition by 20 or more days. Efforts to improve PR establishment in dense bermudagrass suggest chemicals that injure existing bermudagrass can improve PR establishment, but cause unacceptable turf discoloration. Mechanical methods to disrupt the bermudagrass canopy had less effect on PR establishment than chemical treatments. / Master of Science

Studies were conducted in the field and in containers in Mississippi from 2017-2019 to optimize Italian ryegrass control in corn production. Most fall-applied residual herbicides provided ≥ 90% Italian ryegrass control 56 days after treatment (DAT) in both field and container experiments. Oxyflurofen provided 95% Italian ryegrass control 28 DAT but only 81% control 56 DAT in field plots. S-metolachlor plus atrazine followed by paraquat produced the highest return on investment for both site-years. The timing of removal study indicates the optimum time to remove Italian ryegrass relative to corn planting is approximately three to four weeks prior to planting. In the droplet size study, Italian ryegrass control when S-metolachlor was sprayed with the TTI was lower than when S-metolachlor was sprayed with the AIXR in containers 28 DAT. Italian ryegrass control when paraquat was sprayed with the AIXR was greater than when paraquat was sprayed with the TTI.

No description available.