Molecular genetic discrimination of Buffel grass genotypes and F1 hybrids for breeding purposes using amplified fragment length polymorphism analyses

Buffel grass (Cenchrus ciliaris L.) is an apomictic species that is widely adapted to arid and semi‐arid, tropical and warm climates. Six apomictic cultivars used as male parents, one sexual line used as the female parents and 15 putative F1 genotypes were studied using the amplified fragment length polymorphism (AFLP) technique for their evaluation and recognition. The NTSYS programme and Jaccard's Index were used to establish the genetic similarity; and a phenogram was constructed. A total of 152 bands was recorded. Three primer combinations were sufficient to identify the genotypes. The maximum proportion of polymorphisms was 0·835, and 0·510 of the polymorphisms consisted in individual bands that strictly diagnosed unique genotypes. Texas 4464 and Americana cultivars were the most different from the sexual line, indicating that they might be the best genotypes for future crossing. Two hybrids were identified among F1 material to demonstrate the usefulness of the AFLP technique in characterizing genotypes and recognizing hybrids in Buffel grass for breeding purposes.     

Participatory variety development for sorghum in Burkina Faso: Farmers’ selection and farmers’ criteria

Sorghum (Sorghum bicolor (L.) Moench) is the staple crop of Burkina Faso in West Africa where guinea race landraces are grown in low-input cropping systems. National and international breeding programs have had little success in disseminating modern varieties based on high yield potential caudatum or kafir race breeding materials, mostly introduced from other countries. It has been argued that the breeding objectives were not sufficiently oriented towards the farmers’ needs and preferences, and that they did not target the prevailing growing conditions of Burkina Faso. The objectives of the present article are (i) to identify and examine farmers’ selection criteria for sorghum varieties in the Centre-West of Burkina Faso, (ii) to compare these criteria with the breeder's agronomic observations and standard practices, and (iii) to show how the criteria of both farmers and breeders can be effectively integrated into the early stages of a pedigree breeding program. These objectives take into consideration gender differentiation, consistency of selection criteria and the interrelationship of measured quantitative traits, as well as the impact of these traits and criteria on the final selection. The present paper is based on a pedigree breeding program that was carried out over three years (2001–2003) in two villages of Burkina Faso. Options for integrating farmers’ selection expertise with that of the breeders’ were examined. Participatory selection was initiated with 53 F3/F4 progenies in field trials managed by farmers using rating and voting exercises. The breeders measured and analysed the agronomic data while the farmers evaluated a large number of progenies by means of their three most important selection criteria and a general appreciation. Farmers’ initial choices remained consistent in the selection exercises (voting) performed in subsequent years. The farmers’ methods for defining traits turned out to be more multivariate than the breeders’ formal understanding of these same traits. This was especially so for the criteria of grain quality, earliness, and productivity for which the farmers’ definition encompasses factors such as flour yield and stability across environments. However, rating results between farmer groups were variable. A disagreement between female and male ratings was especially found for the grain quality traits. The results clearly show that farmers can effectively select for traits on the basis of progeny and single plants while pursuing specific agronomic aims such as adaption. Subsequent yield improvement schemes will thus be more efficient in terms of selection intensity related to grain yield. The study is showing the way for breeders to adjust their selection criteria to suit the basic needs of small-scale farmer in semi-arid regions of sub-Saharan Africa.     

Genetic resources and breeding methodologies for improving drought tolerance in wheat

Yield gains from rain-fed wheat (Triticum aestivum L.) production, particularly in areas experiencing intermittent and terminal dry spells, can be realized through integrated breeding with promising genetic and genomic resources using appropriate methodologies. This enables targeted recombination of novel genes for drought tolerance and selection of desirable genotypes. Continuous exploration of new sources of genetic variation and introgression of suitable genes into elite drought-susceptible genotypes, including via transgenic approaches, and the use of genome editing could offer exciting future prospects in acquiring drought-tolerant wheat genotypes. This review highlights the available genetic resources, the major wheat genebanks and databases, as well as the breeding methodologies for drought tolerance in wheat, including prebreeding, conventional breeding, hybrid breeding, and genomics-assisted breeding. The potential of genetic modification through the transgenic and genome-editing approaches is also discussed. Emphasis is placed on how best these breeding methods can be brought together to develop strategies aimed at improving drought tolerance in wheat.     

油菜杂交种宁杂21号及其双亲苗期在盐胁迫条件下差异表达基因分析

为了解甘蓝型油菜杂种优势在盐胁迫中的表现,遏制减产,以油菜强优势杂交种宁杂21号及其亲本为材 料,通过转录组测序,筛选鉴定得到1078个芽苗期差异表达基因（DEG）与耐盐杂种优势密切相关,并能被已有盐胁 迫相关QTL注释,部分基因的表达能被荧光定量PCR验证,说明所得DEG具有可靠性,有潜在的油菜耐盐育种价 值。杂交组合中耐盐杂种优势相关DEG表达模式与母本更为类似,大部分表现为正调控,功能倾向于生物合成的 同化作用,而表达模式类似父本的DEG其功能倾向于氧化还原等调节作用。本研究还对耐盐性杂种优势特异的 SNP位点进行了预测和注释,以期为杂交油菜耐盐分子标记的开发以及耐盐育种提供理论依据。     

Ideotype breeding for submergence tolerance and cooking quality by marker-assisted selection in rice

Submergence tolerance and jasmine-like cooking quality are desirable for rice varieties grown in rainfed and irrigated lowland ecosystems in the Mekong region of Southeast Asia. Hybridization between varieties IR57514 and Kao Dawk Mali 105 (KDML105) was initiated with the goal of producing an ideotype that combines submergence tolerance and jasmine-like cooking quality. Through the single seed descent (SSD) method, a large population of recombinant inbred lines (RILs) was developed, and we demonstrated the potential of using marker-assisted selection (MAS) in the identification of the ideotype from the offspring. Four markers, R10783Indel, Waxy, Aromarker and GT11, were used to select the favored alleles of the Sub1, Wx, badh2 and SSIIa loci, respectively. The ideotype was classified into two groups: ideotype1 (ID1), carrying the Sub1^IR, badh2^KD, Wx^KD and SSIIa^KD alleles and consisting of 66 RILs and ideotype2 (ID2), carrying the Sub1^IR, badh2^KD, Wx^KD and SSIIa^IR alleles and consisting of 31 RILs. Submergence tolerance, cooking quality, grain quality and agronomic characteristics of the IDs were evaluated and compared with those of the parents. All of the ID1 lines exhibited submergence tolerance and jasmine-like cooking quality and displayed a low amylose content, a fragrance and a high alkali spreading value, whereas the ID2s showed the same characteristics as ID1, except for a low alkali spreading value, which was inherited from IR57514. A wide range of agronomic characteristics was observed in both of the ID groups, and some of the IDs were superior in the yield component, as compared to their parents. This study provides further support that the precision of markers used in MAS can enhance the development of ideotypes in rice.     

Simultaneous selection for seed and forage production in cocksfoot (Dactylis glomerata): application of drought tolerance and susceptibility indices

An experiment was conducted to estimate drought tolerance of some cocksfoot genotypes based on seed and forage yield and related indices (including tolerance index, mean productivity, geometric mean productivity, reduction percentage index, stress tolerance index and stress susceptibility index) and to identify relationships between measured traits. Twenty‐five genotypes were evaluated in the field under control and drought‐stress environments over 2 years. The results revealed a high variation for seed yield and forage yield and the measured indices under both moisture conditions. No correlation was observed between seed yield and forage yield under the control treatment, but this correlation was positively significant under the water‐stress treatment. Drought‐tolerant and susceptible genotypes were identified based on seed and forage yield performance. Genotypes 2, 4 and 7 had high seed yield, while genotypes 7 and 10 had high forage yield under both stressed and non‐stressed conditions and were identified as the most tolerant genotypes in each category. The results also revealed that genotypes 1, 2, 4, 6, 7, 8 and 24 had relatively high seed and forage yield in both control and drought‐stressed conditions. These genotypes can be used for further studies to improve both seed and forage yields concurrently.     

分子标记辅助选育甘蓝型油菜高油酸pol TCMS不育两用系及其恢复系

高油酸油菜的食用品质、营养价值、贮存和加工品质较高,在食用、工业和药用等领域都发挥重要的作用.为获得高油酸油菜不育系和恢复系,以高油酸油菜J-3111为供体亲本,采用回交转育与分子标记辅助选择相结合的育种策略,将高油酸优良等位基因(fad2基因)导入到甘蓝型油菜波里马细胞质温敏雄性不育(pol TCMS)两用系616A...