SUMMARYThe environmental conditions and test duration in rainfall simulators have been major constraints to find reliable differences in preharvest sprouting (PHS) among wheat cultivars. This study aimed to elucidate the temperature conditions and degree-days (DD) that enable higher discrimination of genotypes in a PHS test. Thirteen genotypes with different degrees of PHS (BR 18, BRS 220, CD 104, CD 105, CD 108, CD 114, CD 116, Frontana, IPR 085, IPR 128, IPR 136, OR1 and Safira) were evaluated in a rainfall simulator, during four years, conducting two trials per year. The tests were carried on 20 spikes per cultivar, kept in a vertical position on Styrofoam plates, spaced 10 cm between rows and 5 cm within the row. The air temperature data were recorded on a thermograph and the DD were calculated from the mean daily air temperature assuming a base temperature of 4 °C. The Falling Number (FN) parameter and germination percentage (GP) data were averaged for each test. The temperatures (minimum, mean and maximum) and the DD were regressed and correlated with FN and GP. Any increase in the minimum and mean air temperature and accumulated DD decreased FN values and increased GP. Higher genotypic discrimination was achieved at an average air temperature of 21.5 °C and 35 DD. These values can be used as reference to set simulated rain testing condition for screening genotype for PHS based on FN or pericarp rupture of grains.
The hectoliter weight or test weight is an important wheat quality parameter for international trade and is traditionally evaluated on devices with a volume of 250, 500, 1000 or 1100 ml. At the experimental level, especially in crop improvement and in greenhouse studies, the amount of grain is often insufficient to determine hectoliter weight. The present work aimed to evaluate the feasibility of using a new 15.30 ml microchondrometer to evaluate hectoliter weight. The testing process was carried out in two steps: (i) To evaluate the need to compress wheat grains inside the microchondrometer cylinder with weights of 0, 4.4, 8.8 and 13.2 kg, and (ii) To verify the effect of different piston weights (4.0, 9.52, 17.56, 28.44 and 31.69 g). A comparison of four compression treatments and five piston weights between 250 ml and 15.30 ml chondrometers were performed by Spearman's correlation coefficient and t-test. The results showed a highly significant correlation coefficient (r=0.99) between the two apparatus and lack of significance for compression and piston weights. The 15.30 ml microchondrometer, in addition to allowing better characterization in small grain samples, will also help to discard unwanted genotypes early in the selection process.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.