QTL mapping for benzoxazinoid content, preharvest sprouting, α-amylase activity, and leaf rust resistance in rye (Secale cereale L.).

Mapping population of recombinant inbred lines (RILs) representing 541 × Ot1-3 cross exhibited wide variations of benzoxazinoid (BX) content in leaves and roots, brown rust resistance, α-amylase activity in the grain, and resistance to preharvest sprouting. QTL mapping of major BX species using a DArT-based map revealed a complex genetic architecture underlying the production of these main secondary metabolites engaged in stress and allelopathy responses. The synthesis of BX in leaves and roots was found to be regulated by different QTL. The QTL for the BX content, rust resistance, α-amylase activity, and preharvest sprouting partially overlapped; this points to their common genetic regulation by a definite subset of genes. Only one QTL for BX located on chromosome 7R coincided with the loci of the ScBx genes, which were mapped as two clusters on chromosomes 5RS (Bx3-Bx5) and 7R (Bx1-Bx2). The QTL common for several BX species, rust resistance, preharvest sprouting, and α-amylase activity are interesting objects for further exploration aimed at developing common markers for these important agronomic traits.

Identification of Single Nucleotide Polymorphisms Associated with Brown Rust Resistance, α-Amylase Activity and Pre-harvest Sprouting in Rye (Secale cereale L.).

Rye is a crop with relatively high resistance to biotic and abiotic stresses. However, the resistance to brown rust (Puccinia recondita f. sp. secalis) and pre-harvest sprouting are still not satisfactory. High α-amylase activity is also among the main disadvantages of this species. Therefore, effective tools, e.g. molecular markers, allowing precise and environmentally independent selection of favourable alleles are desirable. In the present study, two kinds of association mapping-genome-wide association mapping (GWAM) based on sequences of DArTSeq markers and candidate gene association mapping (CGAM) based on sequences of ScBx genes-were chosen for development of molecular markers fulfilling these criteria. The analysed population consisted of 149 diverse inbred lines (DILs). Altogether, 67 and 11 single nucleotide polymorphisms (SNPs) identified in, respectively, GWAM and CGAM, were significantly associated with the investigated traits: 2 SNPs with resistance to brown rust, 71 SNPs with resistance to pre-harvest sprouting and 5 SNPs with α-amylase activity in the grain. Fifteen SNPs were stable across all environments. The highest number (13) of environmentally stable SNPs was associated with pre-harvest sprouting resistance. The test employing the Kompetitive Allele Specific PCR method proved the versatility of four markers identified in both GWAM and CGAM.

Performance of winter triticale lines under high disease (Fusarium head blight) pressure.

Resistance to Fusarium head blight of 29 winter triticale lines and 3 cultivars was evaluated. Triticale was sown in field experiments in two locations. At flowering, triticale heads were inoculated with three Fusarium culmorum isolates. FHB index was scored and after the harvest percentage of Fusarium damaged kernels was assessed. Grain was analyzed for a content of trichothecenes B (deoxynivalenol and derivatives, nivalenol) and zearalenone. The average FHB indexes were similar in both locations and amounted 19.8% in Radzików, and 19.9%. in Cerekwica. Percentage of Fusarium damaged kernels was higher in Cerekwica (53.7%) than in Radzików (26.8%). An average content of DON in Radzików amounted to 8.690 ppm and was lower than in the second locaiion--19.543 ppm. In Cerekwica there were also large quantities of NIV in grain. The average content was 10.048 ppm, while in Radzików it was very low--0.324 ppm. Considerable amounts of DON derivatives in both locations were detected (1,815 ppm of 3AcDON and 1,913 ppm of 15AcDON). The content of the ZON in the grain from Cerekwica was very high and amounted to 1123 ppb, while in Radzików it was 6 times lower--200 ppb. Relationships between FHB index and mycotoxin contents were statistically insignificant in both locations. In contrast, FDK percentages correlated significantly with concentration of mycotoxins. In both locations the parallel experiments with 36 winter wheat were carried out. Triticale proved to be less infected than wheat. However, the content of trichothecenes, was higher in triticale grain than in wheat grain.

The relationship between grain hardness, dough mixing parameters and bread-making quality in winter wheat.

The influence of grain hardness, determined by using molecular markers and physical methods (near-infrared (NIR) technique and particle size index-PSI) on dough characteristics, which in turn were determined with the use of a farinograph and reomixer, as well as bread-making properties were studied. The material covered 24 winter wheat genotypes differing in grain hardness. The field experiment was conducted at standard and increased levels of nitrogen fertilization. Results of molecular analyses were in agreement with those obtained by the use of physical methods for soft-grained lines. Some lines classified as hard (by physical methods) appeared to have the wild-type Pina and Pinb alleles, similar to soft lines. Differences in dough and bread-making properties between lines classified as hard and soft on the basis of molecular data appeared to be of less significance than the differences between lines classified as hard and soft on the basis of physical analyses of grain texture. Values of relative grain hardness at the increased nitrogen fertilization level were significantly higher. At both fertilization levels the NIR parameter determining grain hardness was significantly positively correlated with the wet gluten and sedimentation values, with most of the rheological parameters and bread yield. Values of this parameter correlated with quality characteristics in a higher degree than values of particle size index.

Factors affecting usefulness of triticale grain for bioethanol production.

BACKGROUND: Triticale grain could be a useful material for bioethanol production. The aim of this study was to examine how grain cultivar, nitrogen fertilisation level, location and year affect the starch content in triticale grain and which method of starch determination, polarimetric, enzymatic or near-infrared transmission (NIT), gives the best prediction of real bioethanol productivity from triticale grain. RESULTS: It was found that the starch content in triticale grain was correlated positively with test weight and 1000-kernel weight but negatively with falling number and protein content. All factors, i.e. cultivar, nitrogen fertilisation level, location and year, as well as the intrinsic interaction between these factors, had a significant effect on the starch level in triticale grain. The NIT procedure of starch determination gave the best results in predicting the real yield of ethanol obtained on the basis of classic fermentation (95% match), while the enzymatic and polarimetric methods corresponded with the real results at levels of 89-90 and 78-82% respectively. CONCLUSION: Grain growth conditions related to location and nitrogen fertilisation level had the most noticeable effect on grain starch content, while grain yield per hectare had the most significant effect on ethanol productivity.

Genetic variation in the efficiency of nitrogen utilization and photosynthetic activity of flag leaves among the old and modern germplasm of winter wheat.

Genotypic variation in major components of the efficiency of nitrogen utilization and photosynthetic activity of flag leaves among old (released 1881-1963) and modern (released 1969-2003) cultivars of winter wheat was studied in field conditions under varied N fertilization levels (110, 90 and 80 kg N ha-1). Significant genotypic differences were observed for all characters. Their heritabilities ranged from 0.37 to 0.93 and were the lowest for the leaf efficiency of gas exchange, photosynthetic rate, straw N content and the economic index of N utilization efficiency (NUE). Some modern cultivars exhibited an enhanced tolerance to N shortage and several attributes of efficient N utilization (e.g. later senescing and more photosynthetically active flag leaves, increased ability to redistribute N into grains). The genotypes may serve as donors of appropriate characteristics for breeding. The observed cultivar-by-fertilization interactions suggest, however, that evaluations under diverse fertilization regimes may be necessary when searching for improved wheat efficiency and adaptation to less favourable environments.