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Tomato yellow leaf curl virus (TYLCV) responsible for tomato yellow leaf curl disease (TYLCD) causes a substantial decrease in tomato (Solanum lycopersicum L.) yield worldwide. The use of resistant variety as a sustainable management strategy has been advocated. Tremendous progress has been made in genetically characterizing the resistance genes (R gene) in tomato. Breeding tomato for TYLCV resistance has been based mostly on Ty-3 as a race-specific resistance gene by introgression originating from wild tomato species relatives. Improvement or development of a cultivar is achievable through the use of marker-assisted selection (MAS). Therefore, precise and easy use of gene-targeted markers would be of significant importance for selection in breeding programs. The present study was undertaken to develop a new marker based on Ty-3 gene sequence that can be used for MAS in TYLCV resistant tomato breeding program. The new developed marker was named ACY. The reliability and accuracy of ACY were evaluated against those of Ty-3 linked marker P6-25 through screening of commercial resistant and susceptible tomato hybrids, and genetic segregation using F2 population derived from a commercial resistant hybrid AG208. With the use of bioinformatics and DNA sequencing analysis tools, deletion of 10 nucleotides was observed in Ty-3 gene sequence for susceptible tomato variety. ACY is a co-dominant indel-based marker that produced clear and strong polymorphic band patterns for resistant plant distinguishing it from its susceptible counterpart. The obtained result correlates with 3:1 segregation ratio of single resistant dominant gene inheritance, which depicted ACY as gene-tag functional marker. This marker is currently in use for screening 968 hybrids varieties and one thousand breeding lines of tomato varieties stocked in Jiangsu Green Port Modern Agriculture Development Company (Green Port). So far, ACY has been used to identify 56 hybrids and 51 breeding lines. These newly detected breeding lines were regarded as potential source of resistance for tomato breeding. This work exploited the sequence of Ty-3 and subsequently contributed to the development of molecular marker ACY to aid phenotypic selection. We thus recommend this marker to breeders, which is suitable for marker-assisted selection in tomato. [ABSTRACT FROM AUTHOR]

Drought is a widespread problem in crop growing areas and a threat to food security worldwide. Mulching has become an important practice for maintaining soil moisture, reducing weed growth, mitigating soil erosion and improving soil temperatures in arid and semiarid areas. In northeast China, winter snow is heavy and spring drought frequently occurs, partially due to the loss of melted snow water by evaporation in spring. As such, this study assessed the use of plastic mulching in potato crops to minimize drought by accumulating and reserving water from winter snowfall. In field experiments conducted at two locations in the Heilongjiang Province, China (Keshan in 2011 and 2013, Heihe in 2011 and 2012), black and colorless transparent films were used as mulch during the thickest snow from late winter to early spring. The effects of plastic mulching on soil moisture content and temperature at various soil depths and its influence on potato growth and yield were evaluated. The results showed that film mulching increased the temperature and moisture content of the plow layer (0–10 cm). Black film retained more solid snow than colorless film. The black and colorless films advanced potato emergence by 7 and 14 days, respectively, compared with the control; higher temperatures under the colorless film resulted in earlier emergence than under the black film. The colorless and black film mulching increased soil water contents by 2.5 and 1.5 percentage points, respectively, compared with the control. Average tuber yield over the three-year study at both sites increased by 68.6% and 110.9% with black and colorless film, respectively, with yield increases more apparent in the year with spring drought. The effect of film mulching on yield mainly depended on differences in soil water content between mulching treatments and the control. Snow conserved by winter film mulching supplied water to the plow layer. Our results revealed that film mulching in winter significantly increases soil moisture content, ensures good stand establishment, and effectively solves a severe problem with spring drought in northeast China. [ABSTRACT FROM AUTHOR]