‘Helete Güneşi’, a New Walnut Cultivar with Late Leafing, Early Harvest Date, and Superior Nut Traits

‘Helete Güneşi’ was selected among different genotypes obtained from crossing ‘Maraş 18’ × ‘Chandler’ in Turkey. The present study compares phenological and pomological traits of ‘Helete Güneşi’ with those of its parents so as to scale their performances. ‘Helete Güneşi’ staged leaf out on 22 April, whereas its parents, ‘Chandler’ and ‘Maraş 18’, did on 20 and 12 April, respectively. The harvest date of ‘Helete Güneşi’ was as early as 17 September, whereas ‘Chandler’ and ‘Maraş 18’ began to be harvested on 5 October and 15 September, respectively. Defoliation in ‘Helete Güneşi’ occurred about 1 month earlier than ‘Chandler’. The nut weight and kernel percentage of ‘Helete Güneşi’ were 13.41 g and 53.39%, respectively, whereas in ‘Chandler’ the values were 12.73 g and 48.23%, respectively, but were 14.62 g and 53.76% in ‘Maraş 18’. ‘Helete Güneşi’ had a higher yield value compared to its parents. The results demonstrated that ‘Helete Güneşi’ has superior traits in being selected for late leafing date, early harvest date, high yield, and good nut quality. Therefore, it can be considered as a valuable genetic resource in future breeding programs around the world.

Correlations between Some Horticultural Traits in Walnut

Correlation and causal relationships among 21 horticultural traits were determined using 71 walnut genotypes selected from seven valleys in Kerman Province, Iran. Pearson's correlation coefficient was calculated. Kernel percentage and blight susceptibility were used as dependent variables in a stepwise regression model to determine predictor variables. Direct and indirect effects of each independent variable were calculated using path analysis. A highly significant correlation was observed between lateral bearing habit and yield. Lateral-bearing trees were also more susceptible to blight and winter cold than terminal bearers. Kernel and nut weights, shell thickness, and difficulty of extracting kernel halves were the most important traits accounting for kernel variation. Kernel weight and difficulty extracting kernel halves had the strongest positive direct effects and nut weight the most negative. Flowering habit, nut shape, and leafing date had positive direct effects on blight susceptibility, but the large residual effects suggest there are other important determinant traits for blight susceptibility, which were not considered in this study.

The effect of leaf phenology of overstory trees on the reproductive success of an understory shrub, Staphylea bumalda DC

The effects of the leaf phenology of canopy trees on the reproductive success of an entomophilous, self-incompatible shrub, Staphylea bumalda DC. were examined in a deciduous broad-leaved forest in northern Japan. The amount of light reaching a particular understory shrub from spring to early summer was determined by the leafing date of surrounding canopy species. Variation in leafing date of canopy species affected flower and fruit production by the understory shrub. These results suggest that reproductive success of understory shrubs depends in part on the leaf phenology of canopy trees.Key words: phenology, deciduous broad-leaved forest, fruit set, resource limitation.