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To understand the genetic mechanism of wheat pre-harvest sprouting (PHS) in wheat breeding, it is significant to explore marker loci and candidate genes associated with PHS resistance using intact spikes. In this study, a total of 207 wheat varieties (lines) from China and 16,686 SNP markers were analyzed in wheat whole genome. The mixed liner model (Q + K) was used to analyze PHS phenotypic data in three environments. Genome-wide association study showed that there were abundant phenotypic variations in different environments and wheat varieties (lines). The coefficient of variation was 0.34 and 0.25, the polymorphic information content of value (PIC) was from 0.01 to 0.38, and the attenuation distance of whole genome LD was 3 Mb. The population structure and principal component analysis revealed that 207 wheat varieties (lines) could be divided into three subgroups. GWAS results indicated that 34 SNP markers were detected, which were significantly associated with pre-harvest sprouting at P < 0.001. They were located on chromosomes 3A, 3B, 4A, 4B, 5D, 6A, 6B, 6D, 7B, and 7D, and each explained 5.55%-11.63% of phenotypic variation. There were 16 markers loci detected in more than two environments, and the marker Np_Ex_c14101_22,012,676 on 6B chromosome detected in E1, E2, and average environment. Meanwhile, 13 candidate genes were screened out by mining association loci with large phenotypic effect value and stable inheritance. TraesCS3A01G589400LC, TraesCS6B01G138600/TraesCS6B01G516700LC/TraesCS6B01G548900LC, TraesCS6D01G103600, and TraesCS7B01G200100 could affect seed dormancy by regulating the sensitivity of endogenous ABA in plants. The F-box proteins were encoded by TraesCS3B01G415900LC, TraesCS6A01G144700LC, and TraesCS6B01G294800, which played major roles in plant hormone signal transduction, light signal transduction, and flower organ development. TraesCS6A01G108800, TraesCS6B01G138200/TraesCS6B01G293700 encoded Myb transcription factor family. These candidate genes are important genes related to wheat sprouting. [ABSTRACT FROM AUTHOR]

We successfully identified a novel and unique OsbZIP transcription factor, OsbZIP09, whose mutants exhibited longer seeds and less severe pre-harvest sprouting than the wild type, but shared similar germination rate as the wild type under normal germination conditions. The expression of OsbZIP09 was induced by abscisic acid (ABA) and declined as the germination process. As a nucleus-localized transcription factor, the conserved binding motif of OsbZIP09 was identified via DNA affinity purification sequencing technique. Further evidences indicated that OsbZIP09 directly enhanced the expression of ABA catabolism gene ABA8ox1 , thus reducing ABA accumulation. In addition, OsbZIP09 also directly bound to the promoter of LEA3 gene to inhibit its expression, thus further alleviating the suppressive effect of ABA on seed germination. These results demonstrated that OsbZIP09 likely functions as a brake of the ABA pathway to attenuate the inhibitory effect of ABA on rice seed germination via dual strategies. [ABSTRACT FROM AUTHOR]

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Background and objectives: Preharvest sprouting in wheat reduces quality and impacts farmer profitability. The international recognized falling number test can be used to measure that damage. Trying to understand the complex interactions that cause a reduction in wheat quality, equating to low falling number levels, is challenging. An alternative research approach to replicated experiments was to use a multiseason dataset of load‐by‐load delivery information to investigate whether correlations between falling number levels and 40 climate measurements could be identified. Findings: This study used over 250,000 falling number data points from individual truckloads tested during seven harvests in Western Australia. The analyses identified relative humidity measured at the maximum temperature and daily temperature range as having consistent correlations with falling number levels over multiple seasons. Other climate measurements were also observed to have significant correlations with falling number, but these were less consistent within and between seasons. Conclusions: The linkage of humidity and temperature range levels in the period before harvest commences to the occurrence of low falling number levels helps to further understand the complex interactions that change starch quality. Significance and novelty: The findings demonstrate that value can be obtained from the use of a large, nonexperimentally designed dataset. [ABSTRACT FROM AUTHOR]

Pre-harvest sprouting (PHS) represents a worldwide major problem in wheat production, because it causes huge loss of grain quality. PHS occurs when germination of grains takes place in the spike before harvest and it is influenced by high humidity. The goal of this study was to find QTLs (quantitative trait loci) on chromosomal regions from Romanian wheat and the identification of specific markers that can be used for plant breeding in order to improve resistance to pre-harvest sprouting. The parental lines with different sensibility to pre-harvest sprouting (Turda 95-sensible, Turda 18-94-resistant, Lovrin 32-sensible, Fundulea 29 - resistant) were used for the genotypic characterization using microsatellite markers. A total of 119 from 640 SSR (simple sequence repeats) markers used on the parental lines indicated polymorphism. The initial primer test with the polymorphic markers on the cross lines: Turda 95(S) x Turda 18-94(R), Turda 95(S) x Fundulea 29 (R), Turda 18-94(R) x Lovrin 32 (S) showed that the cross between Turda 95(S) x Turda 18-94(R) had the highest number of segregating markers in the population. 111 F2 lines of the cross Turda 95(S) x Turda 18-94(R) now are being genotypic and phenotypic characterized in order to detect the QTLs underlying pre-harvest sprouting resistance. [ABSTRACT FROM AUTHOR]

Abstract: Four preharvest sprouting (PHS) tolerance-associated markers MST101, wmc104, Xgwm155, and Vp1B3, were used to screen 95 Chinese landraces and historical varieties of wheat (Triticum aestivum L.), and aimed at assessing the efficiency of these markers in selecting genotypes with higher PHS tolerance. Among the 95 genotypes tested, 57, 19, and 19 accessions had germination indexes (GI) of less than 30%, 30–60%, and over 60%, respectively. The relationships between the variation of the PCR products of the 4 markers and germination indexes of the tested materials were analyzed. Variations at Vp1B3 and Xgwm155 were associated with PHS response, but the sequence-tagged site (STS) marker MST101 and sequence-tagged microsatellite site (STMS) marker wmc104 were not. Vp1B3 was more effective than Xgwm155 for selecting PHS resistant varieties. The selection efficiency will be improved if both markers are used. [Copyright &y& Elsevier]

For wheat (Triticum aestivum), periods of prolonged rainfall and high humidity after the grain has ripened and before it can be harvested can contribute to, so called pre-harvest sprouting (PHS), which can be considered as a premature germination. PHS can be defined a complex quantitative character having two important components: sprouting score and falling number. The two these components are controlled by gene effects which are predominant of additive nature. Our research have been conducted on parental, F1, F2) backcross generations means, from 4 cyclic crosses with common parents differing in their reaction to PHS and falling number. Broad sense heritability coefficients for PHS score showed high values in the case of majority hybrids that indicate the important role of genotype in phenotypic expression of reaction to sprouting. Concerning to falling number, broad sense heritability coefficients had smaller values. For wheat as a self pollinated crop, is preferable to be used narrow sense heritability which reflects additive genetic contribution to phenotypic expression of sprouting or falling number, because only additive gene effects can be fixed to progeny. When PHS score, or falling number have high values for narrow sense heritability (higher 50), is recommended the beginning of selection in F2 and in these cases can be successful applied pedigree selection. Concluding, high heritabilities associated with other genetic parameters can be important tools at hand of breeders. They indicated that wheat selection for PHS tolerance or falling number would be effective in populations involving crosses of sensitive and tolerant parents. [ABSTRACT FROM AUTHOR]

An abstract of the article "Genetic Study of Pre-Harvest Sporouting Tolerance in Winter Wheat," by Nicolae Lupu and colleagues is presented.

Wheat is a crop with an extremely short period between harvest and next crop initiation. Therefore, concerning to the seed that will be used has to be taken a fast decision. Finally, the farmer has the responsibility for a good crop based on seeds with high quality (Nelson, 1997). The use of certified seed from recognized producers is the best option. The quality certificate gives you the guarantee that variety is what you wanted; the seed accomplish a minimum physical purity; there are not foreign seeds and in the field and laboratory existed checks before harvest and sale. In this experiment were used 25 samples from Romanian winter wheat lines tested during 2005-2007. Three samples by 10g were analyzed to determinate Fusarium attack, black point, pre-harvest sprouting and healthy seed percentage. At 10 wheat varieties with these symptoms, in three replications, at germinating laboratory of ITCSMS Dolj were also analyzed germination level and 1000 kernel weight. The attack recorded for Fusarium was among 4% (Dor) and 17.2% (Simnic30 variety). From this point of view, comparative with check variety Dropia, the following variants: Simnic30, Lovrin34, Gruia, Alex, Bezostaia, Rapid, Hambar and Izvor were inferior, statistically assured, while Dor variety was significantly superior. Attack level oscillated among 0.3% (Flamura84) and 18.5% (Junona). Check variety Dropia recorded a low attack by 2.3%. At the same incidence were: Romulus, Simnic30, Rapid, Alex, Glosa, Faur and Fundulea4 which nearby Flamura85 and Hambar also presented their superiority against the experiment average by 7%. The highest attack percentage was recorded for black point, with values among 19.7% (Holda) and 51.1% (Izvor). Check variety Dropia also recorded a high incidence of this disease 46.7%, most of the varieties being it superior from this point of view. With better results comparative with the average percentage (36.6%) were: Jiana, Briana, Alex, Gloria, Crina, Simnic30, Bezostaia and Holda. Regarding to germination, in generally, the grains with pre-harvest sprouting were very significant inferior against healthy grains indifferently by the variety. Another analyzed element was the weight of 1000 grains. The grains with Fusarium attack, at all samples, presented a very significant decrease of 1000 grains weight, while the pre-harvest sprouting grains had a very significant increase of 1000 grains weight caused by the water content. In generally, the main tested varieties presented a higher 1000 grains weight value at pre-harvest sprouting grains except: Fundulea4, Rapid and Dropia varieties. [ABSTRACT FROM AUTHOR]