Preharvest Sprouting Assessment in Wheat Genotypes Influenced by Temperature and Degree Days

Abstract

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.

Using big data to predict the likelihood of low falling numbers in wheat

“…Furthermore, there are many other conditions that, in addition to rainfall, influence the occurrence of PHS (Mares & Mrva, ). An additional challenge with PHS has been the range of observed responses (Barnard & Smith, ; Clarke, Christensen, & DePauw, ; Gooding, Ellis, Shewry, & Schofield, ; Jiménez et al, ; Lunn, Kettlewell, Major, & Scott, ; Okuyama, Fonseca Junior, Caramori, & Kohli, ; Ross et al, ; Shorter, Munro, & Hodgkinson, ; Smith & Gooding, ; Trethowan, Rajaram, & Ellison, ). Contributing to the diversity of responses will be environments studied (i.e., climatic; field vs. glasshouse design; and with and without intervention), diverse genotypes, and different ways to measure PHS (i.e., from dormancy to germination tests and falling number).…”

“…LSD t test, with values in the same column and group (pre-or postharvest readiness) followed by the same letter not significantly different. Kettlewell, Major, & Scott, 2002;Okuyama, Fonseca Junior, Caramori, & Kohli, 2017;Ross et al, 2012;Shorter, Munro, & Hodgkinson, 2005;Smith & Gooding, 1999;Trethowan, Rajaram, & Ellison, 1996). Contributing to the diversity of responses will be environments studied (i.e., climatic; field vs. glasshouse design; and with and without intervention), diverse genotypes, and different ways to measure PHS (i.e., from dormancy to germination tests and falling number).…”

Pre-harvest Sprouting Tolerance of Triticale Genotypes in Brazil

“…Ears were exposed to nebulization for 42 hours, 68 hours and 42 hours in 2016, 2017 and 2018 growing seasons, respectively. This method has been utilized successfully in the main wheat breeding programs in Brazil, for pre-harvest sprouting resistant genotypes selection (Franco et al, 2009;Okuyama et al, 2017). The experiment design was completely randomized, with two replications, being the experimental unit made of 20 ears.…”

Caracterização De Genótipos De Triticale Para Tolerância À Germinação Na Espiga

“…Vários fatores podem contribuir para uma maior tolerância à germinação na espiga, como a redução dos níveis de alfa-amilase nos grãos, a presença de inibidores de germinação, redução da absorção de água pelos grãos e respostas alteradas para hormônios (FLINTHAM, 2000;ZANETTI et al, 2000;HIMI et al, 2002;MARES et al, 2005). Adicionalmente, a falta de dormência adequada das sementes é a principal razão para a PHS, sendo destacada como uma característica governada por múltiplos genes (LI et al, 2004 (BASSOI et al, 2006;FRANCO et al, 2009;OKUYAMA et al, 2017 Embora a variabilidade genética existente no triticale para a resistência à PHS e para o NQ seja menor que a disponível no trigo, ela parece ser suficiente para que, através do melhoramento genético, novas cultivares superiores possam ser geradas (NEDEL et al 1983b;HAESAERT;DE BAETS, 1996;OETTLER, 2005;ALARU et al 2008;BIZOVA et al 2011).…”