This study evaluated options and obstacles to strengthening food security through breeding a staple crop in a developing country, using the case of quality of bread wheat in Tajikistan as an example.

Staple crop yield, quality and sustainable production are critical for domestic food security in developing countries. In Tajikistan, both seed-borne diseases and protein quality impair the yield and the quality of the major staple crop, wheat. Here, we used a detailed two-year survey of fields on 21 wheat-producing farms in Tajikistan, combined with lab analyses on seed health and protein quality, to investigate the presence of seed-borne diseases and bread-making quality in Tajik wheat. Seed samples were collected for the analysis of: (i) the presence of common bunt (Tilletia spp.) using the centrifuge wash test, (ii) the major pathogenic fungi on/in the seed using the agar plate test and (iii) the protein amount and size distribution using size-exclusion high-performance liquid chromatography (SE-HPLC). Field occurrence of common bunt and loose smut was generally low (3 farms in year one (14%) showed common bunt occurrence), but the presence of fungi was observed microscopically on most seed samples (on seeds from 19 out of 21 farms = 91%). Tilletia laevis was the dominant agent in common bunt (present in 19 farms compared to T. tritici present in 6 farms). Altogether, 18 different fungi were identified from seed samples by microscopy. Protein composition, measured with high-performance liquid chromatography as protein amount and size distribution (known to correlate with bread-making quality), differed significantly between samples from different farms and years, although the farm type and land elevation of the farm were not the determinants of the protein composition. The presence of certain fungi on the seed correlated significantly with the protein quality and could then have an impact on the bread-making quality of the Tajik wheat. The presence of seed-borne diseases, a low protein content and weak gluten were the characteristics of the majority of the grain samples, mostly irrespective of farm type and farmer’s knowledge. For sustainable development of the Tajik farming systems, and to strengthen the food security of the country, the knowledge of Tajik farmers needs to be increased independently of farm type; in general, plant breeding is required and certified seeds need to be made available throughout the country.

Wheat seed-borne diseases are among the major constraints reducing crop yield and the quality of seed and grain. In this study we aimed to evaluate the type and prevalence of fungal seed-borne diseases in Tajik wheat seed samples. Particular emphasis was given to common bunt resistance in advanced wheat breeding materials. Furthermore, we aimed to identify options for improving the seed quality. Seed samples collected from two different locations in Tajikistan were tested by conventional seed-health testing methods for presence of seed-borne diseases. Nineteen advanced wheat breeding lines and three varieties collected from the Tajik wheat breeding program were screened using an artificial inoculation test for their response to common bunt. Significant differences were found between the locations and genotypes concerning presence of common bunt and black point. Fourteen fungal species, where most of them are pathogenic for wheat, were identified in the seed samples. Tilletia laevis, T. tritici, Bipolaris ...

One of the factors affecting wheat productivity in Tajikistan is the emergence and spread of rust diseases - yellow, stem and leaf rust. Emerging new races of pathogens virulent to existing resistance genes in wheat varieties create new challenges. The selection of rust resistant wheat genotypes is usually carried out by studying phenotypic traits in seedlings (seedling resistance) and in adult plants (adult plant resistance) and analysis using available molecular markers. It has been established that races of yellow rust affecting wheat varieties in Tajikistan are aggressive and are characterized by high temperature tolerance. According to the results of studies, it was found that the highest degree of resistance to yellow rust is observed in varieties Sarvar, Vakhdat, AIKT-20 and Fayzbakhsh, in old-grown varieties Kaboi Pandzhakent and Surkhak-5688, as well as in the line PASTOR/3/VORON. Most of the new wheat varieties have the following groups of rust resistance genes: Sr31/Yr9/Lr26, Sr38/Yr17/Lr37, Yr30/Sr2/Lr27 и Yr18/Lr34/Sr5. In this regard, it is necessary to constantly monitor the spread and development of rust diseases, as well as to select wheat varieties for resistance to rust using both traditional and modern methods using molecular markers.

Non-satisfactory bread-making quality in wheat, a Tajik staple, hampers food security in Tajikistan and calls for plant breeding efforts. Here, methods were searched for to study grain protein composition, which is of use for Tajik plant breeding to improve bread-making quality. Size-exclusion high-performance liquid chromatography (SE-HPLC) was used to determine protein composition in 22 wheat varieties and breeding lines grown in two locations, which were then compared with the specific protein composition evaluated using electrophoresis and previous results from Tajik breeding and farmer-grown wheat. As Tajik wheat generally showed a large variation in high-molecular-weight glutenin subunit (HMW-GS) composition, with several allelic variants in the same line, single-seed selection was required when using this methodology in breeding for improved bread-making quality, and such an evaluation willalso result in more homogenous lines for protein composition. SE-HPLC was found to be a suitable tool to evaluate protein composition in the current Tajik wheat material with a heterogeneous protein composition, which might be advantageous for adaptation to the local and future climate. However, more easy-to-handle and high-throughput methods, e.g., marker-assisted selection, could be preferable alternatives for studying protein composition in wheat and for use in breeding for increased bread-making quality to increase food security in Tajikistan.