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.     

Highly client-oriented breeding,using local preferences and selection,produces widely adapted rice varieties

When explicit measures are taken to account for the needs of clients (farmers and consumers) it results in highly client-oriented breeding. This involves the participation of farmers to specify the design of desirable varieties and, once they are produced, their testing without delay with the target clients in the target environments. The term highly client-oriented breeding (COB) explains the purpose of farmer involvement – the deliberate achievement of a high degree of client orientation – rather than simply explaining the process of farmers participating in plant breeding (participatory plant breeding). Client-oriented breeding is sometimes based on the preferences of relatively few farmers in a small area, so a possible drawback is that it will produce varieties that are too locally adapted. We describe the testing of varieties in the High Barind Tract (HBT) of Bangladesh from a COB programme carried out in Chitwan district, Nepal. The two best lines, Judi 582 and Judi 567, yielded 19–50% more during the T. Aman season and 106% more during the Aus season than check varieties in the HBT. Research to determine farmers’ preferences and adoption consistently showed these varieties were preferred over all available alternatives. The new varieties were broadly adapted as they were superior in all the three rice-growing seasons over varying levels of inputs. This broad adaptation could be explained by the breeding method: the generations were advanced in two contrasting seasons and each generation was grown on a different farmer's field under different management and planting dates. Because the segregating generations were grown under moderate and fluctuating levels of nitrogen, it is to be expected that genotypes with good nitrogen use efficiency will be selected that can also respond to added nitrogen. Overall, the cost-effectiveness of COB was high as it produced widely adapted genotypes from a small breeding programme, and knowledge of farmers’ preferences increased the efficiency of targeting new germplasm.     

Has the introduction of modern rice varieties changed rice genetic diversity in a high-altitude region of Nepal?

We surveyed the uptake of three modern rice varieties by farmers in high-altitude villages in the Kaski district of Nepal and found that their uptake had displaced some traditional landraces in the district. The three varieties, Machhapuchhre-3 (M-3), Machhapuchhre-9 (M-9) and Lumle 2, were developed using client-oriented, participatory plant breeding methods and the first was introduced to farmers in 1996. By 2004 up to 60% of the land area was used to grow these modern varieties. Molecular markers (SSR) were used to assay levels of genetic diversity to test if adoption of modern varieties in the place of landraces had changed genetic diversity. The modern varieties were found to contain diverse alleles with a high proportion from the local parent variety, Chhomrong Dhan. We found a high level of allelic richness in the landraces, and although seven had been dropped in favour of the modern varieties, other diverse landraces were still being cultivated by farmers in the study villages on up to 40% of the rice area. Genetic diversity may be maintained even when landraces are displaced by modern varieties. Using a model we found that the partial replacement of landraces increased genetic diversity if the modern varieties were adopted on up to 65% of the area. Only above these levels did overall diversity decline.     

Comparing decentralized participatory breeding with on-station conventional sorghum breeding in Nicaragua: I. Agronomic performance

Few studies have assessed the effective gains achieved by collaborative decentralized participatory breeding, in terms of yield and other agronomic traits, in comparison with centralized conventional breeding using the same breeding schemes. Our study concerned an experience of participatory improvement of tortillero sorghum for low-input cropping systems in northern Nicaragua. It set out to compare the effect of two breeding schemes simultaneously managed on-station and on-farm. Two synthetic populations were used as sources of genetic variability. The study was designed to distinguish between three “selection modes”: farmers’ selection on-farm (FoF), breeder’ selection on-station (BoS) and breeder's selection on-farm (BoF). After two selection cycles, we found that FoF selection reduced phenotypic variability as much as BoS selection. In general, BoS selection produced higher-yielding lines under the target on-farm conditions. But FoF selection was more effective in promoting lines with higher values for an index of agronomic suitability (IAS), expressing a better balance between earliness, plant height, grain size and yield. Such genotypes might cope more easily with local environmental constraints and farmers’ preferences. BoF selection did not prove to be effective for either yield or IAS. This research shows the need for close collaboration between farmers and breeders as well as complementarities between the selection phases managed on-farm and on-station, to make breeding for difficult environments fully efficient.     

Molecular Breeding for Rainfed Lowland Rice in the Mekong Region

Abstract

In the past 20 years, the rice-breeding program in Thailand had little success in developing new cultivars to replace Kao Dawk Mali 105 (KDML105) and Kao Khor 6 (RD6) for the rainfed lowland rice environments. The main reason for the poor adoption of new cultivars by farmers is the susceptibility to diseases and unacceptable grain qualities. The conventional breeding program also takes at least 15 years from initial crossing to the release of new cultivars. A new breeding strategy can be established to shorten the period for cultivar improvement by using marker-assisted selection (MAS), rapid generations advance (RGA), and early generation testing in multi-locations for grain yield and qualities. Four generation of MAS backcross breeding were conducted to transfer genes and QTL for bacterial blight resistance (BLB), submergence tolerance (SUB), brown plant hopper resistance (BPH) and blast resistance (BL) into KDML105. Selected backcross lines, introgressed with target gene/QTL, were tolerant to SUB and resistant to BLB, BPH and BL. The agronomic performance and grain quality of these lines were as good as or better than KDML105.     

丰产、优质、抗病油用亚麻品种“轮选一号”的选育

利用亚麻显性雄性核不育基因,通过多亲本杂交和互交,组建原始基础群,对不育株进行抗枯萎病抗性的轮回选择,以改良群体,从而培育出了以抗枯萎病为主、兼抗立枯病,丰产、优质的油用亚麻品种——轮选一号,为油用亚麻抗枯萎病育种开辟了一条新的有效途径。     

杂交水稻三系不育系选育的实践与思考

回顾了杂交水稻三系不育系15 a来选育的实践,总结了选育杂交水稻三系不育系的经验与体会.1)利用籼粳交加花药培养快速稳定技术选育三系不育系及其保持系,育种难度大,成效低;2)选育优质不育系,低代品质鉴定是关键;3)不育系异交结实率的选择,应从柱头外露率和田间自然异交结实率两方面考虑;4)有针对性地进行个别性状的遗传改良选育新的不育系,可以达到事半功倍的效果;5)选育抗稻瘟病水稻不育系是非常必要的,应加强这方面的工作.     

双季稻机插技术在江西的应用现状、存在问题及推广对策

利用江西省双季稻区8个县24个乡镇的调查数据,对双季稻机插技术在江西的应用现状、存在问题进行了研究。结果表明,机插种植方式的成本低于其他种植方式、收益高于其他种植方式;机插种植方式的推广受到农户的年龄、文化程度、土地规模、资金等的影响,年龄越小、文化程度越高、土地经营规模越大的农户机插比例相对较高;限制机插技术推广的主要因素包括育秧技术复杂、购机及机插费用高、田块小和分散等;积极推进土地集约化进程、加强机插核心技术的培训指导力度、建立稳定的政策资金扶持机制、创新机插服务模式、积极宣传并做好示范区建设等是促进机插技术推广的重要举措。     

Agronomic performance of rice breeding lines selected based on plant traits or grain yield

Selection for yield per se has greatly contributed to yield improvement in many crops. It is expected that selection based on plant traits is more effective in increasing crop yield potential. This study was conducted to compare the effectiveness of trait-based and yield-based selection in increasing rice yield and to determine whether lines with ideotype traits have the potential to express higher yield under optimal crop management conditions. Lines were selected based on plant traits or on grain yield measured in a breeder's replicated yield trial. The main target traits for selection were plant height, leaf and panicle morphology, grain size, total dry weight, and grain-filling percentage. Yield performance of trait-based selection was compared with that of yield-based selection in an agronomic trial with optimum crop management for three seasons. Trait-based selection increased leaf area index and total dry weight but reduced spikelet number per m² and harvest index compared with yield-based selection. Consequently, selection based on plant traits did not increase grain yield compared with selection based on yield per se. In one of the three seasons, yield of trait-based selection was significantly lower than that of yield-based selection. Among all tested breeding lines, maximum yield was produced by yield-based selection and minimum yield came from trait-based selection. These results suggest that lines with ideotype traits did not express higher grain yield than lines selected based on yield per se under optimal crop management conditions, and yield-based selection was as effective in increasing rice grain yield as trait-based selection in the late generations of the breeding cycle.     

Revisiting rice breeding methods – evaluating the use of rapid generation advance (RGA) for routine rice breeding

Rice production needs to increase in the future in order to meet increasing demands. The development of new improved and higher yielding varieties more quickly will be needed to meet this demand. However, most rice breeding programmes in the world have not changed in several decades. In this article, we revisit the evidence in favour of using rapid generation advance (RGA) as a routine breeding method. We describe preliminary activities at the International Rice Research Institute (IRRI) to re-establish RGA on a large scale as the main breeding method for irrigated rice breeding. We also describe experiences from the early adoption at the Bangladesh Rice Research Institute. Evaluation of RGA breeding lines at IRRI for yield, flowering time and plant height indicated transgressive segregation for all traits. Some RGA lines were also higher yielding than the check varieties. The cost advantages of using RGA compared to the pedigree method were also empirically determined by performing an economic analysis. This indicated that RGA is several times more cost effective and advantages will be realized after 1 year even if facilities need to be built. Based on our experience, and previous independent research empirically testing the RGA method in rice, we recommend that this method should be implemented for routine rice breeding in order to improve breeding efficiency.     

寒地水稻花培育种选择效率分析

 对25年寒地水稻花培育种与同期常规育种统计资料进行了比较分析。经花培入选的产量鉴定新品系的选择效率为16.94%,是同期常规新品系选择效率11.34%的1.49倍;经花培育成的审定品种的选择效率为0.93%,是同期常规育成审定品种选择效率0.28%的3.32倍。从花培育成品种的推广种植面积与常规育成品种比较分析,花培育种与常规育种有同样好的选择效果。     

Acceptance and competitiveness of new improved wheat varieties by smallholder farmers

We conducted this research because earlier research revealed that Pakistani farmers were growing 8–10-year-old wheat (Triticum aestivum L.) varieties and hence not benefitting from the recent advances in wheat breeding. Participatory varietal selection (PVS) trials were conducted to have farmers validate and include newly released wheat varieties into seed-production stream to speed up replacement of old and obsolete wheat varieties by farmer-preferred new high-yielding varieties. Fourteen new varieties recommended for irrigated and eight for rainfed environments were evaluated in this research involving smallholder farmers in food-deficit districts of Pakistan. Collaborating farmers preferred 10 varieties from the PVS trials, eight of which were germplasm from the International Maize and Wheat Improvement Center (CIMMYT) that yielded on average 5–17% more grain than local checks. Local checks used in the PVS trials in Sindh and Khyber Pakhtunkhwa were old improved varieties. Greater yield advantage from new varieties over local checks was reported from rainfed environments and areas where old local checks were used. The PVS research showed the possibility of ensuring food security of smallholder farmers as new high-yielding varieties gave an additional 0.3 –0.5 tons of grain per ha, sufficient to feed two to three persons per year. Research also revealed that innovative farmers in rainfed regions grew wheat varieties recommended for irrigated regions to identify high-yielding wheat varieties with stable performance. Feedback by farmers to wheat breeding research system was to develop even higher yielding new wheat varieties with diseases resistance to replace old and obsolete varieties to boost food security.     

Importance of basic cultivation techniques to increase irrigated rice yields in Tanzania

The productivity of irrigated rice is low in Tanzania. We hypothesized that this is caused by the absence of a packaged application of basic cultivation techniques. A baseline survey of 31 rice irrigation schemes across the country revealed that a large proportion of fields were cultivated without a technical package. Thus, a package was introduced to each of the 31 schemes through a farmer-to-farmer (FTF) extension approach. First, selected key farmers (KFs) were trained with the basic cultivation techniques at agricultural training institutes. Second, the KFs transferred their knowledge to intermediate farmers (IFs) by working together at a demo-field established in each scheme. Third, the KFs and IFs exhibited the rice performance to other farmers (OFs). The paddy yield across the 31 schemes greatly increased from the pre-training level of 2.4 t ha^?1 to 3.6 t ha^?1after the FTF extension. However, the farmer interviews in the four selected schemes suggested that the technical package was not adopted by all farmers owing to the time-consuming nature of the FTF extension. It was inferred from our study that the low productivity of irrigated rice is caused by the absence of basic cultivation techniques in Tanzania. However, the post-training yield remained relatively low compared with high-yields (4.3–8.4 t ha^?1) recorded in cultivar selection trials and high-performing schemes in the county. This “yield gap” could be partly ascribed to the insufficient technical diffusion and the technique-dependent adoption among OFs.     

HMW-GS标记辅助选育优质小麦新品系

为加速优质小麦育种进程,将聚合杂交、HMW-GS辅助选择与常规育种程序结合,在小麦品种烟农19、济麦20、郑优6号、百农66不同杂交组合F2代进行HMW-GS标记辅助选择,经连续多代鉴定筛选,选育出14个含优质HMW-GS或HMW-GS组合的小麦新品系.鉴定结果表明,14个新品系的蛋白质含量、沉降值、湿面筋含量、面筋指...     

现代玉米育种技术研究进展与前瞻

过去的30年里玉米育种技术取得了长足的发展。分子标记、生物技术、双单倍体等得到了快速发展与广泛应用,自交系和杂交种的选育方法发生了飞跃。本文就分子育种技术、后代选择方法、转基因育种技术、双单倍体技术等方面进行概括总结,并展望未来10～20年玉米育种技术发展的前景。     

Determination of efficient test sites for evaluation of peanut breeding lines using the CSM-CROPGRO-peanut model

Efficient testing of crop breeding lines requires a set of complementary test sites that adequately sample the target environments with minimal duplication. Such test sites have been derived from actual multi-environmental trial (MET) data, which often have a limitation with respect to their environmental coverage. However, this limitation can be overcome using a crop simulation model. The goal of this study was to determine the efficient test sites for METs of peanut breeding lines in Thailand using the CSM-CROPGRO-Peanut model. The model was used to simulate pod yield for 17 peanut lines at all peanut production areas in Thailand that included 76 locations in the early-rainy season, 39 locations in the mid-rainy season and 47 locations in the dry season for 30 years. The simulated data were used to sub-divide the locations for each season into groups using cluster analysis and the genotype plus genotype × environment (GGE) biplot method. Six sets of test sites were obtained based on different scenarios for site selection that included combinations of geographical distribution and representation of location-groups as determined by the two methods. Set 1 was based on geographic distribution. Sets 2–4 were based on location grouping by cluster analysis, but with the sites distributed in all regions (Set 2), or only in the north (Set 3) or northeast (Set 4). Set 5 consisted of the sites currently used, and Set 6 was based on location grouping by the GGE biplot. Although Sets 2 and 6 appeared to capture more genotype × location interaction than the others, performance rankings of the test genotypes were almost the same for all sets. They were, therefore, considered equally effective for breeding line evaluation. The final selection was then based on the convenience, and consequently the cost, for conducting the METs. Set 4 was considered most preferable in this regard. This study demonstrated the usefulness of a crop simulation model as a tool in determining the most efficient test sites for the evaluation of peanut breeding lines.     

大豆疫霉根腐病抗病资源筛选及抗性遗传研究

在人工接种条件下，用大豆疫霉根腐病菌1号生理小种对580份大豆材料（生产上主栽品种、即将推广的新品系，以及大豆资源材料）进行鉴定，筛选出一批抗大豆疫霉根腐病的品种和资源材料，为大豆疫霉根腐病重发生区提供了种植品种，也为抗疫霉根腐病育种提供了杂交亲本。并对其抗性遗传进行初步研究和探讨。     

玉米单倍体精准加倍效果及超快捷育种方法探讨

基于幼胚拯救的化学加倍技术路线,对难以自然加倍基础材料（华美1号）的单倍体进行精准加倍后,加倍株率高达75.83%,自交结实率高达50.39%,是自然加倍效率的49.89倍和69.97倍,多粒（≥7粒）结实果穗高达80.1%,提出单倍体人工精准加倍概念。多年实践发现,精准加倍能实质性改善单倍体散粉质量,花序表现为整分支或全序散粉,平均散粉期达4 d,抖花序就可采集充裕的花粉。开展以高通量幼胚拯救精准加倍与DH₀自交和测交同步实施为主要技术关键的“玉米超快捷育种方法及流程”研究取得重要成果,经多年规模化验证,关键技术指标达到8个月时限内完成DH系的创制、鉴选,并同步获得相应测交种,经过3年8个月时限即可育成优异组合进入预试,提出结合轮回选择的超快捷双轮回育种技术应用策略。     

优质蛋白玉米的分子标记辅助选择

综述了应用于优质蛋白玉米种质辅助选择的分子标记,提出了优质蛋白玉米的分子标记辅助选择策略;通过对回交家系赖氨酸分析和SSR分子标记检测结果,对该技术的可靠性进行了验证;考虑到成本核算和可操作性,认为该分子标记辅助选择技术,应用于育种实践是非常经济有效的。     

玉米杂交诱导单倍生殖(单倍体)选育自交系技术规范(暂行版)

汇总国内外单倍体育种研究理论与经验,经美国著名单倍体育种家张铭堂指导,组装集成出本规范,供试用参考。本规范制定了杂交诱导单倍生殖方法选育自交系的基本操作程序,将单倍体杂交诱导、子粒鉴选、植株确认、自然与人工加倍及双单倍体获得5个环节作出技术规定。在每个环节都还有技术关键(特别是人工加倍等多属商业机密范畴)在试用与待熟化。经多年实践验证,按此规范程序,只需2～3个生育世代即可批量选育出遗传高度纯合自交系。