Linking wood anatomy with growth vigour and susceptibility to alternate bearing in composite apple and pear trees.

Excess vegetative growth and irregular fruit-bearing are often undesirable in horticultural practice. However, the biological mechanisms underlying these traits in fruit trees are not fully understood. Here, we tested if growth vigour and susceptibility of apple and pear trees to alternate fruit-bearing are associated with vascular anatomy. We examined anatomical traits related to water transport and nutrient storage in young woody shoots and roots of 15 different scion/rootstock cultivars of apple and pear trees. In addition, soil and leaf water potentials were measured across a drought period. We found a positive correlation between the mean vessel diameter of roots and the annual shoot length. Vigorously growing trees also maintained less negative midday leaf water potential during drought. Furthermore, we observed a close negative correlation between the proportions of total parenchyma in the shoots and the alternate bearing index. Based on anatomical proxies, our results suggest that xylem transport efficiency of rootstocks is linked to growth vigour of both apple and pear trees, while limited carbohydrate storage capacity of scions may be associated with increased susceptibility to alternate bearing. These findings can be useful for the breeding of new cultivars of commercially important fruit trees.

Land use change impacts on floods at the catchment scale: Challenges and opportunities for future research.

Research gaps in understanding flood changes at the catchment scale caused by changes in forest management, agricultural practices, artificial drainage, and terracing are identified. Potential strategies in addressing these gaps are proposed, such as complex systems approaches to link processes across time scales, long-term experiments on physical-chemical-biological process interactions, and a focus on connectivity and patterns across spatial scales. It is suggested that these strategies will stimulate new research that coherently addresses the issues across hydrology, soil and agricultural sciences, forest engineering, forest ecology, and geomorphology.

A new H-2 congenic strain B10.ABQ/Ph carrying a recombinant H-2 haplotype derived from balanced lethal stock Ttf/t12.

A new H-2 congenic strain, B10.ABQ/Ph, has been established. It carries the recombinant H-2 haplotype derived from balanced lethal stock Ttf/t12. The recombinant H-2 haplotype was designated bq5 and possesses the following alleles at individual loci of the H-2 complex: Kb A beta b A alpha b E beta b or q E alpha b or q Sb or q Dq Lq.