The relationship between commercial cotton cultivars with varying Meloidogyne incognita resistance genes and yield

摘要

Small plot cotton cultivar trials (12 trials) were conducted from 2016 to 2019 in fields infested with Meloidogyne incognita. Entries in these trials included commercial cultivars with partial and high resistance to M. incognita, as well as cultivars with no known resistance. Different resistant groups were created based on different cotton seed companies and their descriptions of the M. incognita resistant cultivars. Groups were none (susceptible); partial resistance found in Stoneville or Fibermax cultivars (PR-FM/ST); partial resistance found in PhytoGen cultivars (PR-PHY); resistance (unknown gene(s)) in Deltapine cultivars (NR-DP); and highly resistant cultivars homozygous for RK1 and RK2 resistant genes in PhytoGen cultivars (HR-PHY). The highest lint yields using a mixed model analysis were found in the PR-FM/ST (1,396?kg lint/ha), HR-PHY (1,327?kg lint/ha), and PR-PHY (1,314?kg lint/ha) groups. Yield for NR-DP (1,234?kg lint/ha) was not different (p??0.05) than yield for susceptible cultivars (1,243?kg lint/ha). If the older resistant cultivars from Deltapine and PhytoGen (those with only Roundup Ready? herbicide technology) were removed from the analysis, then HR-PHY yields increased by 133?kg of lint/ha to 1,460?kg lint/ha and NR-DP yields remained approximately unchanged (1,227?kg lint/ha). Newer HR-PHY had much improved yield over the first HR-PHY cultivars. Newer HR-PHY averaged 17% higher yield than the susceptible group. LOG 10 (M. incognita eggs/500 cm 3 soil ?1) were highest for the susceptible cultivars (3.2), followed by PR-FM/ST (2.6), NR-DP (2.4), PR-PHY (2.1), and lowest with HR-PHY (1.4). The newer HR-PHY cultivars (those with ENLIST? herbicide technology) combine excellent yields (17% higher than susceptible cultivars) with high (96%) suppression of M. incognita.Small plot cotton cultivar trials (12 trials) were conducted from 2016 to 2019 in fields infested with Meloidogyne incognita. Entries in these trials included commercial cultivars with partial and high resistance to M. incognita, as well as cultivars with no known resistance. Different resistant groups were created based on different cotton seed companies and their descriptions of the M. incognita resistant cultivars. Groups were none (susceptible); partial resistance found in Stoneville or Fibermax cultivars (PR-FM/ST); partial resistance found in PhytoGen cultivars (PR-PHY); resistance (unknown gene(s)) in Deltapine cultivars (NR-DP); and highly resistant cultivars homozygous for RK1 and RK2 resistant genes in PhytoGen cultivars (HR-PHY). The highest lint yields using a mixed model analysis were found in the PR-FM/ST (1,396?kg lint/ha), HR-PHY (1,327?kg lint/ha), and PR-PHY (1,314?kg lint/ha) groups. Yield for NR-DP (1,234?kg lint/ha) was not different (p??0.05) than yield for susceptible cultivars (1,243?kg lint/ha). If the older resistant cultivars from Deltapine and PhytoGen (those with only Roundup Ready? herbicide technology) were removed from the analysis, then HR-PHY yields increased by 133?kg of lint/ha to 1,460?kg lint/ha and NR-DP yields remained approximately unchanged (1,227?kg lint/ha). Newer HR-PHY had much improved yield over the first HR-PHY cultivars. Newer HR-PHY averaged 17% higher yield than the susceptible group. LOG 10 (M. incognita eggs/500 cm 3 soil ?1) were highest for the susceptible cultivars (3.2), followed by PR-FM/ST (2.6), NR-DP (2.4), PR-PHY (2.1), and lowest with HR-PHY (1.4). The newer HR-PHY cultivars (those with ENLIST? herbicide technology) combine excellent yields (17% higher than susceptible cultivars) with high (96%) suppression of M. incognita.