The cotton aphid, Aphis gossypii Glover (Homoptera: Aphididae), is an important cotton pest in northern China, especially in the seedling stage of cotton. After large scale commercial use of transgenic Bt cotton, cotton aphids became one of the most important cotton pests. A 2‐year study was conducted to evaluate the role of four winter wheat varieties that were resistant or susceptible to wheat aphid, Sitobion avenae Fabricius (Homoptera: Aphididae), in conserving arthropod natural enemies and suppressing cotton aphids in a wheat–cotton relay intercropping system in northern China. The results indicated that wheat–cotton intercropping preserved and augmented natural enemies more than a monoculture of cotton. The density of natural enemies in cotton was significantly different among relay‐intercropping fields with different wheat varieties. The highest density of natural enemies and low cotton aphid populations were found in the treatment of cotton in relay intercropped with the wheat variety Lovrin10, which is susceptible to wheat aphid. The lowest density of predators and parasitoids associated with high cotton aphid populations were found with the wheat variety KOK1679, which is resistant to wheat aphid. The results showed that wheat varieties that are susceptible or moderately resistant to wheat aphid might reduce cotton aphids more effectively than an aphid‐resistant variety in the intercropping system by enhancing predators to suppress cotton aphids during the cotton seedling stage.

To analyse the inheritance of fruit ring rot (FRR) resistance and to screen for microsatellite markers linked to resistance⁄susceptibility, 875 apple hybrid seedlings (Malus domestica, Jonathan · Golden Delicious) were inoculated with five isolates of Botryosphaeria dothidea in 2 years (2008 and 2009). The results indicated that incidence and non-incidence were qualitatively segregated, and incidence was dominant to non-incidence. The variation in susceptibility within this population was attributed to the segregation of three major genes. For the phenotype of incidence, the severity of lesion development was a quantitative trait. From 230 published microsatellite primer pairs, six markers were identified that were linked to the susceptibility to FRR. located in LG12 and LG2, respectively, were linked to susceptibility to the pathogen isolate Mx1, and their map distances to the susceptibility loci were 8.2 and 5.1 centimorgan (cM), respectively. CH01e01-120 and CH02c02b-100, which were linked to susceptibility to Ls1, were located in LG14 and LG4, and the map distances to the susceptibility loci were 16.9 and 8.4 cM, respectively. CH05d11-150 and CH03a03-230, linked to susceptibility to Lw048, were located in LG12 and LG14; for both of them, the map distance was 13.4 cM.

Fruit shape index (FSI) is one of the most important traits in apple. In this study, the inheritance of a FSI (ratio between height and diameter at the widest point of the fruit) was analysed in a hybrid population derived from 'Jonathan' 9 'Golden Delicious' (Malus domestica Borkh) using frequency distribution and molecular marker analysis. A binary distribution pattern was observed which matched a 31:1 segregation ratio for small: large FSI scores. This ratio can be explained by the segregation of five independently inheriting single dose loci, whereby high FSI requires the simultaneous absence of all dominant alleles. The joined heritability of these major genes was estimated to be 75.00 and 75.

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BackgroundAlthough protein phosphorylation is an important post-translational modification affecting protein function and metabolism, dynamic changes in this process during ontogenesis remain unexplored in woody angiosperms.MethodsPhosphorylated proteins from leaves of three apple seedlings at juvenile, adult vegetative and reproductive stages were extracted and subjected to alkaline phosphatase pre-treatment. After separating the proteins by two-dimensional gel electrophoresis and phosphoprotein-specific Pro-Q Diamond staining, differentially expressed phosphoproteins were identified by MALDI-TOF-TOF mass spectrometry.ResultsA total of 107 phosphorylated protein spots on nine gels (three ontogenetic phases × three seedlings) were identified by MALDI-TOF-TOF mass spectrometry. The 55 spots of ribulose-1, 5-bisphosphate carboxylase/oxygenase (Rubisco) large-chain fragments varied significantly in protein abundance and degree of phosphorylation among ontogenetic phases. Abundances of the 27 spots corresponding to Rubisco activase declined between juvenile and reproductive phases. More extensively, phosphorylated β-tubulin chain spots with lower isoelectric points were most abundant during juvenile and adult vegetative phases.ConclusionsProtein phosphorylation varied significantly during vegetative phase change and floral transition in apple seedlings. Most of the observed changes were consistent among seedlings and between hybrid populations.