Sharka disease, caused by the plum pox virus (PPV), is one of the major limiting factors for stone fruit crops in Europe and America. In particular, apricot is severely affected suffering significant fruit losses. Thus, PPV resistance is a trait of great interest for the apricot breeding programs currently in progress. In this work, two apricot maps, earlier constructed with the F 1 'Goldrich × Currot' (G×C) and the F 2 'Lito × Lito'-98 (L×L-98) populations, have been improved including 43 and 37 new simple sequence repeat (SSR) loci, respectively, to facilitate PPV resistance trait mapping. Screening of PPV resistance on the segregating populations classified seedling phenotypes into resistant or susceptible. A non-parametric mapping method, based on the Kruskal-Wallis (KW) rank sum test, was initially used to score marker-trait association, and results were confirmed by interval mapping. Contrary to the putative digenic model inferred from the phenotypic segregations, all significant markers for the KW statistic (P<0.005) mapped in a unique region of~21.0 and 20.3 cM located on the upper part of the G1 linkage group in 'G×C' and 'L×L-98' maps, respectively. According to the data, PPV resistance is suggested to be controlled by at least one major dominant locus. The association between three SSRs distributed within this region and the PPV resistance was tested in two additional populations ('Goldrich × Canino' and 'Lito × Lito'-00) and breeding program parents. The marker ssrPaCITA5 showed the highest KW value (P<0.005) in all cases, pointing out its usefulness in marker-assisted selection.

Sunflower (Helianthus annuus L.) seeds contain alpha-tocopherol as the major tocopherol derivative, which accounts for more than 900 g kg 21 total tocopherols. However, four sources of high gammatocopherol content (.850 g kg 21 ) have been developed. First studies on the lines LG-17 and T2100 concluded that the trait in both lines was determined by recessive alleles at the Tph2 locus. The objectives of the present research were (i) to conduct an allelic study on the other two lines, IAST-1 and IAST-540, (ii) to identify markers linked to the

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Two different sunflower lines with increased beta-tocopherol concentration in the seeds, LG-15 and T589, have been developed. The objective of the present research was to conduct a comparative genetic study of the increased beta-tocopherol concentration in both lines. Plants of LG-15 were reciprocally crossed with plants of T589 in 2003. The F 1 , F 2 , BC to LG-15 and BC to T589 seed generations were produced in the same environment in 2004 and analyzed for tocopherol profile. The results indicated a strong environmental effect on the increased levels of beta-tocopherol concentration in LG-15 and T589, which averaged 30.5% and 25. 8%, respectively, in 2003 and 43.2% and 54.0%, respectively, in 2004. The comparison of individual plant means and standard errors of individual plant means for the F 2 and BC generations with those in the non-segregating parental and F 1 generations indicated no transgressive segregation for beta-tocopherol concentration in F 2 or BC seeds. These results suggested that increased beta-tocopherol concentration in both lines is the result of genetic alterations at the same locus.

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