Pollination in crops, as in native ecosystems, is a stepwise process that can be disrupted at any stage. Healthy pollinator populations are critical for adequate visitation, but pollination still might fail if crop management interferes with the attraction and retention of pollinators. Farmers must balance the direct benefits of applying insecticide and managing irrigation rates against their p...

In maize (Zea mays L.) large decreases in kernel number result when low water potentials (Psi(w)) and high temperatures occur during pollination. To gain insight into the basis for the decreased seed set, silk, pollen, and ear-leaf Psi(w), the capability for silk osmotic adjustment, and pollen appearance were measured to determine their relationship to seed set. A multiple-eared or prolific (hi...

How climate-change induced environmental stress may alter the effects of inbreeding in patchy populations of rare species is poorly understood. We investigated the fitness of progeny from experimental self- and cross-pollinations in eight populations of different size of Echium wildpretii, a rare endemic plant of the arid subalpine zone of the Canarian island of Tenerife. As control treatments ...

The production of seed by both selfing and outcrossing, or mixed mating, may be selected for under conditions of variable pollinator availability. Seed production was examined following experimental manipulations of perfect and pistillate flowers of the gynomonoecious plant Silene noctiflora. Style excision experiments in a greenhouse demonstrated that autonomous selfing occurs in the perfect f...

the present experiment was carried out to assess the general combining ability (gca) and specific combining ability (sca) of six important commercial cultivars of gossypium hirsutum l. of venezuela, viz., ‘deltapine 16’, ‘tamcot-sp-21’, ‘cabuyare’, ‘stoneville’, ‘ospino’ and ‘acala 90-1’ and their 15 f1 hybrids, respectively. the data were analyzed using griffing’s model i method ii. significan...

We study a model in which two entities (e.g., plant species, political ideas, ...) compete for space on a plane, starting from randomly distributed seeds, and growing deterministically at possibly diierent rates. An entity which forms an innnite cluster is considered to dominate over the other (which then cannot percolate). We analyze the occurence of such a form of domination in situations in ...

We present a memory-based named-entity recognition system that chunks and labels named entities in a oneshot task. Training and testing on CoNLL-2003 shared task data, we measure the effects of three extensions. First, we incorporate features that signal the presence of wordforms in external, language-specific seed (gazetteer) lists. Second, we build a second-stage stacked classifier that corre...

28 Research on threats to pollination service in agro-ecosystems has focused primarily on 29 the negative impacts of land use change and agricultural practices, such as insecticide use, on 30 pollinator populations. Insecticide use could also affect the pollination process, through non31 lethal impacts on pollinator attraction and post-pollination processes such as pollen viability or 32 pollen...

A small or sparse population may suffer a reduction in fitness owing to Allee effects. Here, we explored effects of plant density on pollination, reproduction and predation in the alpine herb Pedicularis rex over two years. We did not detect a significant difference in the pollination rate or fecundity (fruit set and the initial seed set) before predation between sparse and dense patches in eit...

Most chrysanthemum cultivars are self-incompatible, so it is very difficult to create pure lines that are important in chrysanthemum breeding and theoretical studies. In our previous study, we obtained a self-compatible chrysanthemum cultivar and its self-pollinated seed set was 56.50%. It was interesting that the seed set of its ten progenies ranged from 0% to 37.23%. Examination of the factor...