Submitted to: Rice Technical Working Group Meeting Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 1/1/2006
Publication Date: 2/15/2006
Citation: Boza, E.J., Moldenhauer, K.A., Gibbons, J.W., Lee, F.N., Cartwright, R.D., Jia, Y., Boyette, V., Blocker, M.M. 2006. Field and milling quality analysis of the my1 mapping population in Arkansas [aabstract]. Rice Technical Working Group Meeting Proceedings, Feburary 28, 2006 -March 1, 2006, Houston, Texas. 2006. CDROM. Interpretive Summary:
Technical Abstract: A coordinated effort with Louisiana and Texas as part of the RiceCAP project is under way to evaluate the MY1 RT0034/Cypress mapping population for agronomic characteristics and milling quality. A population of 156 F12 rice lines, the parents (RT0034 and Cypress), and six controls (LaGrue, Madison, Spring, Maybelle, Tranasse, and Presideo) were planted during the 2005 season at the Rice Research and Extension Center (RREC), Stuttgart, AR, on a Crowley silt loam (Fine montmorillonitic thermic Typic Albaqualfs). The experiment was planted in a RCB design with two replications. Each rice line was planted in two row plots approximately 0.6 m long with about 25 cm between rows. Plots were planted at a seeding rate of 2.6 g/m2. Two fungicide applications of Quadris and Quilt mixed at 9 and 21 fl oz/A, respectively, were applied at early booting and about 10 days later for disease control. At germination, some weak stands were observed in some of the plots, and plants were transplanted within the plot to have a more uniform stand throughout the season. About 86% of the population had at least 1 plant every two inches, 9% had an intermediate stand and 5% was thin. Moreover, we did not see variability in maturity between parents. The parents were different in days to heading by only three days, but a range of 39 days was observed in maturity among the progeny evaluated, suggesting transgressive segregation for maturity. Overall, about 65% of the population was headed within 2-5 days, 26% within 6-10 days, 7% within 11-14 days, and 2% was headed within least maturity14 days or more. The effect of heading date and the variability within lines on milling quality is yet to be determined. Although fungicides were applied for disease control, a relatively low level of brown spot disease (Bipolaris oryzae) was observed in the test. The parents of the MY1 mapping population were observed to differ in their disease reaction. Cypress was noted to be unaffected by brown spot; on the other hand, RT0034 had an intermediate reaction in a rating scale from 0 (no infection) to 9 (' 90% of leaf area affected). A great percentage of the population (about 80%) had a resistant reaction (0-3), 18% had an intermediate reaction (4-6), and 2% had a susceptible reaction (7-9). In general, a relatively late planting under Arkansas conditions might help to differentiate the recombinant inbreeding lines for milling quality.