Spot blotch is an important disease of wheat (Triticum aestivum L.) in South Asia. Division of test sites for this disease into homogenous subregions is expected to contribute to more efficient evaluation and better differentiation of cultivars. Data from a collaborative regional program of South Asia conducted by CIMMYT were analyzed to group testing sites into relatively homogenous subregions for spot blotch area under the disease progress curve (AUDPC). Five‐year data of eight locations from Eastern Gangetic Plains Nursery (EGPSN) and five locations of the Eastern Gangetic Plains Yield Trial (EGPYT) conducted in three countries (India, Nepal, and Bangladesh) of South Asia were used. A hierarchical cluster analysis was used to group locations on the basis of genotype × location interaction effects for spot blotch AUDPC. Cluster analysis divided South Asia into two broad regions and four subregions. This classification was not entirely consistent with the geographic distribution of locations, but clusters mostly followed general geographic‐climatic locations. The locations Varanasi (India) and Bhairahawa (Nepal) were identified as the most suitable sites for evaluation of spot blotch, followed by Rampur (Nepal). The major determinant for the clustering was mean temperature. The results suggest that the major wheat region of South Asia can be divided into subregions, which may reduce the cost of resistance evaluation and aid in developing wheat with resistance to this disease.

On-farm participatory varietal selection (PVS) trials are often of two types: mother trials (with all of the entries) and baby trials (each having one, or very few of the entries from the mother trials). We conducted PVS trials on 17 wheat varieties in 12 villages of four districts of Bangladesh over three years but the data were highly unbalanced. Both quantitative and qualitative traits were measured in the on-farm trials. The factors in the trials were both fixed effects (varieties and districts) and random (years and farmers). We used the residual or restricted maximum likelihood (REML) analysis for the mixed model for quantitative traits. For qualitative data on farmers' perceptions, logistic regression procedures were used that are equally applicable to balanced and unbalanced data sets. The REML analysis provided adjusted mean values for quantitative traits for all the varieties, for the mother and baby trials separately, using the data from all years and all locations. It identified varieties BAW 1006 and BAW 1008 that yielded 19-30% more than the control Kanchan and also had a higher 1000-grain weight, were at least as early to flower and had a high overall ranking by farmers in the mother trials. The logistic regression analysis of perception data agreed with the results of the REML analysis as these varieties were most preferred by farmers for grain yield, earlier maturity and better chapatti making quality. The less labour-intensive method of recording qualitative perceptions can usefully replace actual yield measurements, particularly when validated by other participatory measures such as intended and actual adoption. In 2005, BAW 1006 was released as BARI Gom 23 or Bijoy and BAW 1008 as BARI Gom 24 or Prodip for the whole of Bangladesh. The validity of the results of the REML analysis was confirmed by the high early adoption trends of the identified varieties. Since REML is an effective analysis for unbalanced PVS trial data using a mixed model, its wider use by researchers would increase the value of the PVS process.

Farmers’ preference study and informal seed dissemination was carried out through farmer participatory variety selection (PVS) during 2006–2007 to 2008–2009 by the Wheat Research Centre (WRC), Bangladesh Agricultural Research Institute (BARI), Dinajpur, Bangladesh, in collaboration with CIMMYT. Four varieties including widely grown Shatabdi and four advance lines including Ug99 tolerant BAW 1064 were tested in mother-baby trial approach in 8 villages in each year. Mother trials were researcher designed but farmer managed. However, baby trials were designed and managed by farmers themselves. Preference scores of 30 farmers for varieties were recorded two times viz., pre and post-harvest stages. Farmers’ preferred BAW 1064 owing to its 10% yield superiority over the widely grown Shatabdi variety, bolder white grains, larger grains/spike, non-lodging behaviour, earliness and resistance to diseases. This variety was found moderately resistant to Ug99 in Kenya. BAW 1064 was released as BARI Gom 26 in March 2010. After three years of PVS work, 19.4 t seeds reached informally to 969 farmers of 24 PVS villages from only 252 kg source seeds supplied for trials. In 2009–2010, seed production of this variety was done in 44 ha; 33.8 ha in 111 farmers’ fields and 10.2 ha in research stations. Around 150 t seeds were produced that are being used for further testing and multiplication in 2010–2011. Seed dissemination through PVS was much faster than official approach of Bangladesh Agriculture Development Corporation (BADC). Hence, for selection and dissemination of CIMMYT developed Ug99 tolerant lines, farmer-participatory approach is being deployed.

Participatory selection was conducted at the Wheat Research Centre, Bangladesh Agricultural Research Institute (BARI), Dinajpur to facilitate farmers in selecting and disseminating their preferable variety and replace widely cultivated disease susceptible Kanchan to increase wheat yield and production. Farmers' need for wheat variety was identified through participatory rural appraisal in 2002 and impacts were assessed by house hold level survey in 2005. Researches were conducted as mother and baby trials. Scaling-up seed dissemination was carried out through seed supply. BAW1008, Shatabdi, and BAW 1006 produced higher yield in both mother and baby trials and got higher scores for farmers' overall preference. The farmers emphasized on yield together with bold and white grains, more grains/spike, strong stem and other characters during scoring. They identified BAW 966, BAW 1006, BAW 1008, and Shatabdi for good Chapati quality. They expected to cultivate BAW1008, Shatabdi, and BAW 1006 in the following years. Farmer to farmer seed dissemination was highly satisfactory and seeds of Shatabdi reached 47% wheat farmers of the villages in 2004-05. Varietal diversity was increased remarkably and seven varieties were grown in the study villages. The area of Kanchan came down from 100% (in 2002-03) to 24% (in 2005-06). The participating personnel were hopeful to the new concept of plant breeding and expecting its widespread use in the country.

Impacts of participatory variety selection in wheat on agro-economic changes like adoption of new wheat varieties and production technologies, income and attitude change of the wheat farmers, etc. are presented in the paper. There were remarkable changes in production technology adoption, sources of agricultural knowledge, attitude and income changes. Farmers' income was increased to Tk. 11148/ha due to cultivation of new varieties and use of recommended production technologies. Participatory variety selection approach in wheat was found very useful to increase wheat production in the working villages. Widespread use of this approach may be useful throughout the county in other crops also.

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