Genetic maps containing molecular markers are useful tools for the identification of genes underlying quantitative traits (QTLs). Three traits important for plant physiology, i.e. chlorophyll content, sensitivity to GA and sensitivity to ABA, were evaluated for 99 F2 families of the DS2 x RXLl0 rye mapping population. The observed variation in the chlorophyll content in rye leaves was shown to be under the genetic control of four independent QTLs. They were located on the following chromosome arms: 1RL (QChc-1R.I), 3RS (QChc-3R.1), 4RL (QChc-4R.1) and 5RL (QChc-5R.1) The marker-assisted selection of recombinants comprising positively-acting alleles at these loci may significantly increase the chlorophyll content in rye leaves, which should result in a higher efficiency of photosynthesis. A decreasing of plant height in rye is one of the major aims of breeders selecting for lodging resistance. The polymorphism of genes controlling sensitivity to gibberellic acid may be the basis for a potential selection strategy. Three QTLs underlying the sensitivity of rye seedlings to GA were located on chromosomes 5RL (QGar-5R.I), 1RL (QGar-1R.1) and on 7RL (QGar-7R.I). The dwarfing allele of a Dw1 locus present in line RXL10 was mapped in the same position as the QGar-5R.1 gene. Sensitivity to ABA plays an important role in imposing dormancy in rye grain. Three QTLs affecting sensitivity to ABA were found. They were mapped on chromosomes 1RS (QAbr-1R.1), 2R in the centromeric region (QAbr-2R.1) and on 5RL (QAbr-5R.1). QAbr-5R.1, Dw1 and QGar-5R.1 are located in the same position on the distal part of the 5RL chromosome arm, which suggests that they belong to a single locus for a major regulatory gene controlling the development of rye plants.
Analizami objęto dwie populacje F2 mieszańców międzyliniowych żyta oraz zestaw 62 rekombinacyjnych linii wsobnych (RIL-F7) żyta wyprowadzonych z mieszańca 541 × Ot1-3. Potwierdzono istnienie sprzężenia między uprzednio wytypowanymi trzema markerami RAPD, a genem kontrolującym męską sterylność w cytoplazmie C. Dodatkowo zidentyfikowano zestaw pięciu nowych markerów RAPD sprzężonych z genem Rfc1, ale wśród nich tylko jeden wykazywał sprzężenie z genem męskiej sterylności wystarczająco silne dla podjęcia prób wykorzystania go przy selekcjonowaniu materiałów hodowlanych.
Genetic control of a-amylase activity in rye grain was investigated by QTL mapping/based on DS2 x RXL10 intercross consisting of 99 F₅₋₆ families propagated at one location during four vegetation seasons. A wide range of variation in α-amylase activity and transgression effects were found among families and parental lines. This variation was shown to be determined in 40.1 % by 7 significant (LOD score not less than 2.5) and 2 putative QTLs (2 < LOD < 2.5) distributed on all rye chromosomes except 4R. Two significant QTLs located on 3RL and 5RL chromosome arms were expressed each year. The third significant QTL was detected in three years (1RL). The other four significant QTLs (2RL, 5RS, 6RL, 7RL) were found in one year of study. The number and composition of QTLs were specific for a given year varying from three to six. QTLs were not correlated with isoenzyme polymorphisms at the structural α-Amyl loci. A QTL associated with a region containing the α-Amy3 locus was detected on chromosome 5RL. Both high- and low-activity QTL alleles were found in each parental line, which explains the appearance of transgressive recombinants in the segregating population.
Zdefiniowano QTL dla zawartości chlorofilu (Chc) i maksymalnej fotochemicznej aktywności PSII (Fv/Fm) żyta. Materiał do badań stanowiła populacja RIL mieszańca międzyliniowego DS2 × RXL10, złożona z 70 osobników pokolenia F7. Otrzymane wyniki poddano analizie statystycznej; stwierdzono istotne zróżnicowanie obu cech u form rodzicielskich i osobników w populacji mapującej. Nie zaobserwowano istotnej statystycznie korelacji pomiędzy Chc a Fv/Fm; obliczone współczynniki odziedziczalności w szerokim zakresie (HB) wynosiły odpowiednio 56 i 53%. Przy LOD ≥ 2,0 wyznaczono 19 regionów QTL, w tym 9 dla zawartości chlorofilu i 10 dla całkowitej wydajności fotochemicznej PSII. Lokalizowały się one głównie w dystalnych lub centromerowych obszarach chromosomów: 1R, 3R, 5R, 6R, 7R, przy czym na chromosomach 1R, 5R i 6R znalazły się regiony wspólne dla QTL Fv/Fm1 i Fv/Fm5 (1R), Chc8 i Fv/Fm9 (5R) oraz Fv/Fm3 i Fv/Fm10 (6R). Otrzymane QTL dostarczają wstępnej wiedzy o dziedzicznym podłożu zawartości chlorofilu w życie i maksymalnej fotochemicznej aktywności PSII.
Grain quality of rye is often negatively affected by sprouting - a complex trait with a poorly understood genetic background and strong interaction with weather conditions. The aim of this report was to detect the main quantitative trait loci (QTLs) underlying preharvest sprouting resistance in rye, measured as a percentage of sprouted kernels after spraying spikes with water for 7 days. Simple and composite interval mapping, carried out in 3 environments on 94 F₃ and F₄ families of the cross between sprouting-susceptible (541) and sprouting-resistant (Otl-3) inbred lines, revealed 5 QTLs located on chromosome arms IRL, 2RL, 5RL, 6RL and 7RL. The significance of these QTLs was additionally proved by disruptive selection carried out on 5000 F₂ plants of the 541 × Otl-3 cross and continued to the F₅ generation of recombinant inbred lines (RIL), which strongly affected allele frequencies at linked marker loci. Resistance to preharvest sprouting showed dominant inheritance except for QPhs.uas-7R.l (recessive) and QPhs.uas-1R.1 (additive). Results of the present study suggest that introgression of 4-5 QTLs, identified in line Otl-3, should substantially reduce sprouting risk in rye varieties.
Celem badań była ocena możliwości wykorzystania techniki losowej amplifikacji polimorficznego DNA (RAPD) do identyfikacji 16 krajowych odmian pszenżyta ozimego. Poszukiwano polimorficznych fragmentów DNA testując 50 starterów o losowych sekwencjach. Do właściwych badań wybrano 17 starterów w obecności, których amplifikacji uległy sekwencje charakteryzujące się polimorfizmem i dużą stabilnością. Otrzymano 30 polimorficznych fragmentów DNA, różnicujących wszystkie badane odmiany. Markery RAPD wykorzystano do konstrukcji dendrogramu przedstawiającego relacje podobieństwa genetycznego między odmianami.
Location of the loci that control preharvest sprouting and alpha-amylase activity in rye was studied based on intercross S120×S76, consisting of 110 genotypes of F2 and F3 progenies. The genetic map currently consists of 141 loci distributed in 11 linkage groups, covering a distance of 506.4 cM, and was enriched during this study with 24 sequence-specific markers (7 SCARs, 7 SSRs, and 10 STSs). The extended map was applied for composite interval mapping of the loci controlling preharvest sprouting and a-amylase activity, revealing 3 significant QTLs for preharvest sprouting, located on chromosomes 3R, 5R and 6R (in 1999), and one QTL for a-amylase activity found on chromosome 2R (in 2000).
Four F2 mapping populations derived from crosses between rye inbred lines DS2×RXL10, 541×Ot1-3, S120×S76 and 544×Ot0-20 were used to develop a consensus map of chromosome 6R. Thirteen marker loci that were polymorphic in more than one mapping population constituted the basis for the alignment of the four maps using the JoinMap v. 3.0 software package. The consensus map consists of 104 molecular marker loci including RFLPs, RAPDs, AFLPs, SSRs, ISSRs, SCARs, STSs and isozymes. The average distance between the marker loci is 1.3 cM, and the total map length is 135.5 cM. This consensus map may be used as a source of molecular markers for the rapid development of new maps of chromosome 6R in any mapping population.