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The most important applications of genomic selection (GS) in maize breeding is to predict and identify the best untested lines from biparental populations, when the training and validation sets are derived from the same cross. A total of 300 hybrids were generated using doubled haploid lines crossed to single known tester. The test hybrids and checks were evaluated for drought tolerance, grain yield and yield attributes under well‐watered (WW) and water stress at flowering (WSF) conditions during rabi 2018 at Hyderabad and Aurangabad locations. The study was further deep dived and practiced GS using 3352 single‐nucleotide polymorphism (SNP) markers. An extension of the genomic best linear unbiassed predictor that incorporates genotype × environment (GE) interaction was used to predict genotypic values; cross‐validation methods were applied to quantify prediction accuracy. Our results showed that the highest cross‐validation prediction accuracy for grain yield was 0.47 under WSF condition in TPS3, whereas under WW condition, prediction accuracy was 0.44 in TPS2, which is statistically on par with WSF condition. Among the secondary traits, the peak GS accuracies recorded for the traits anthesis silking interval (0.52) and ears per plant (0.48) under WSF. Under both the water regimes, anthesis silking interval and plant height recorded higher prediction accuracy when compared with grain yield. Hence, GS could be practiced for anthesis silking interval and ears per plant under stress condition in maize. Further while optimizing the population size, it was revealed from the study that increasing size of the population increases GS accuracy and TPS2 considered as optimum size of population for GS prediction. [ABSTRACT FROM AUTHOR]

Monoecy and parthenogenesis exist in certain male and female gametophytes of the brown alga Undaria pinnatifida. The inheritance of these traits is not known. In this study, we made a cross between a male and a female gametophyte clone which could exhibit monoecy and parthenogenesis phenotypes, respectively, and obtained their next‐generation gametophyte offspring. We found that under conditions suitable for gametogenesis, all of the male offspring (n = 100) exhibited monoecy phenotype and all of the female offspring (n = 100) only formed oogonia and underwent parthenogenesis, suggesting that monoecy and parthenogenesis phenotypes are inheritable. Then, we established a doubled haploid (DH) population through monoecious selfing and parthenogenesis, and evaluated the young sporophyte growth and the maximum quantum yield (Fv/Fm) of 10 "male" and 10 "female" DH lines. On day 60, the average length of the "male" DH lines was significantly larger than that of the "female" DH lines, while their average Fv/Fm values were not significantly different. Monoecious selfing seemed superior to parthenogenesis as the sporophyte formation efficiency, and the young sporophyte growth was better in the former than in the latter. We also crossed two monoecious gametophytes with another male gametophyte, and a parentage analysis showed success of obtaining hybrid sporophytes, indicating that the female gametes released by the monoecious gametophyte can actually be fertilized by sperm. The approach of establishing a DH population proposed here will be useful in genetic breeding and quantitative trait loci mapping in U. pinnatifida and may be applicable to other kelp species. [ABSTRACT FROM AUTHOR]

Four barley doubled haploid populations were produced by anther culture from the reciprocal crosses between two six-row barley cultivars, ‘Plaisant’ and ‘Orria’; the doubled haploid lines (DHLs) derived from each cross were subsequently assigned to weak or vigorous populations according to the weak or vigorous nature of the originating embryos. Well-formed embryos at day 25 on the induction medium were considered vigorous, whereas embryos maturing later were considered weak. The classification of vigorous and weak was closely associated with the ratio of green to albino plantlets regenerated. A random set of 25 DHLs from each of the four populations were selected for field testing in a replicated trial. Furthermore, a second set consisting of a total of 454 unreplicated DHLs from the four populations were also field assessed for grain yield. Distortion during in vitro culture may impede regeneration of a random array of microspores from a given cross, and may bias genetic estimates of specific trait/marker association in genetic studies. However, no significant differences were detected in this study among the four populations for days to heading, height, grain yield and thousand-kernel-weight when measured on the replicated trial of 100 DHLs, nor for grain yield in the second collection of 454 entries. This suggests that the likelihood of producing improved agronomic pure lines is independent of the direction of crossing and, more importantly, independent of the time when embryos matured in the induction media, at least for these particular six-row cultivars and for the anther culture method used. [ABSTRACT FROM AUTHOR]

This study was conducted to expedite disease-resistance breeding in canola by screening haploid plants against blackleg disease. Microspore-derived haploid plantlets from 14 unrelated crosses were inoculated with Leptosphaeria maculans pycnidiospores and were rated as resistant, intermediate or susceptible. Blackleg-inoculated and control haploid plants were then coichicine-treated to produce doubled haploid (DH) lines. The DH lines thus produced were again screened against blackleg using the cotyledon bioassay. In general, the proportion of the resistant DH lines derived from selected resistant haploid plants was much higher than the proportion of resistant DH lines from control haploid populations. There was no detrimental effect on the survival of haploid plants after the combined treatment of blackleg inoculation and colchicine. The importance of the microenvironment on the final outcome of plant-pathogen interaction in case of non-obligate pathogens is also discussed. [ABSTRACT FROM AUTHOR]

Doubled haploid oilseed rape lines segregating for a transgene inducing herbicide resistance (bar gene) were investigated for the wide mapping of the T-DNA insertion site. Bulk segregant analysis using presence/absence and intensity polymorphisms between the bulks, as well as comparative mapping with a linkage group deriving from another cross, led to the identification of 11 random amplified polymorphic DNA (RAPD) markers tightly or loosely linked to the bar gene. Ten RAPD loci out of 11 were located on the same side of the bar locus, strongly suggesting that the T-DNA integrated in a telomeric or subtelomeric position. The eleventh RAPD marker exhibited a strong segregation distortion, which could be the result of a heteroduplex formation. Comparison of the linkage groups obtained from the two crosses showed different recombination rates between markers, possibly reflecting differences in parental genetic backgrounds. Consequences and potential applications in transgene dispersal safety assessment studies are discussed. [ABSTRACT FROM AUTHOR]

The doubled haploid (DH) wheat line ‘dh 5841’ carrying two translocations from rye, 5DL.5RS and 1BL.1RS, has been crossed to the subline of wheat cultivar ‘Amadeus 7143’ with a 1BL.1RS translocation. The resulting F1 hybrid IJ 98 with a heterozygous 5DL.5DS–5DL.5RS chromosome pair has been used to produce doubled haploids. A total of 57 DH lines were obtained from plantlets regenerated in anther culture after successful colchicine treatment and seed set. These lines were identified regarding the constitution of chromosome 5D (5DL.5DS or 5DL.5RS) by means of isoenzyme marker analysis. Thirty DH lines possessed the 5DL.5DS chromosome, while the remaining 27 lines carried the 5DL.5RS translocation. For some of these lines, the 5DL.5RS chromosome was cytologically confirmed by C-banding. Furthermore, the DH lines were evaluated for their high molecular weight glutenin subunit composition. All possible combinations for the four independent loci — Skdh, Glu-A1, Glu-B1 and Glu-D1 — were detected in only 57 DH lines and no segregation distortion was observed. [ABSTRACT FROM AUTHOR]

Doubled haploid lines derived from anther culture of two Iranian spring wheat genotypes 'Ghods' susceptible and '9106' resistant to yellow rust in Iranian field conditions, and their F1 hybrids were used in this study. Seedlings of 36 doubled haploid lines, selected out of 96 according to their agronomic traits and the two parental genotypes were inoculated with eight races of yellow rust. The parental genotypes ('Ghods' and '9106') were segregating for some of the races but their doubled haploid lines were either resistant or susceptible to them. 'Ghods' was susceptible to three of the races studied but three doubled haploid lines derived from it were resistant to them. Five selected doubled haploids from the '9106' genotype and six from F1 hybrid plants were resistant to all eight races tested. After further investigations in Iranian field conditions it was found that some of these lines can be used as donor genotypes for resistance to yellow rust in wheat breeding programmes. Use of these genotypes should be possible if the French yellow rust races used for selection also represent the dominant races in Iran. It can be concluded that anther culture provides an efficient method for fixing genes of resistance to yellow rust and desirable doubled haploids from F1 plants can be derived. [ABSTRACT FROM AUTHOR]