Male Phenology Research Articles

Male phenology and pollen production of Cupressus sempervirens in Tetouan (Morocco)

Male phenology, processes of microsporogenesis and pollen differentiation were studied for Cupressus sempervirens from the city of Tetouan (Morocco). Five phenological phases are described based on morphological and structural characters. Pollen mother cells stage, meiosis, microspore maturation and pollen development occurred in winter from December to February. Meiotic development shows typical coniferous pattern. Anthesis takes place two months after bud burst. The flowering phenophase takes place over one month and is associated with the main pollen emission period which started in the last week of February 2007. The pollen production of individual trees in C. sempervirens is also estimated. Tree size, cone density and number of pollen grains per cone are investigated. The results indicate that the number of pollen grains per cone and the total pollen production per tree were in the production range to those obtained in anemophilous trees. This study provides the first data on the onset of the pollen season and on the pollen production in C. sempervirens in Morocco and the contribution of this species to the total amount of airborne pollen content in Tetouan city.

Variation in Reproductive Phenology in a Pinus radiata D. Don Seed Orchard in Northern Spain

Summary Reproductive phenology was studied in a Pinus radiata seed orchard, located in northern Spain. Timing of flowering was determined on the basis of data recorded by visual observations made in 2000, 2001 and 2002. The genetic and environmental factors affecting female and male phenology, as well as reproductive synchronization, were studied. The dates of beginning of the receptive phase and pollen shedding varied greatly from year to year but the variation on the sum of degree-days was low. In general, the flowering periods of the different clones overlapped. The clonal differences in the phenology of receptivity and pollen shedding were in most cases statistically significant. The time needed to reach flowering stages was under strong genetic control. Genetic control was stronger for the female than the male flowering process. However, correlations between years were stronger for male than for female flowering phenology. The male flowering clones that best synchronized with the females appeared to be those that started flowering earlier. The phenological overlap index varied greatly among clones, whether male or female, and also among years.

Reproductive phenology in a Norway spruce seed orchard

Reproductive phenology was studied in a Norway spruce seed orchard, located in southern Finland (62°13’N, 25°24’E), consisting of 67 clones from northern Finland (64°–67°N). Timing of flowering was determined on the basis of data recorded by a pollen catch meter during 1984–1995, and visual observations made on grafts in 1989, 1992, 1993 and 1995. The genetic and environmental factors affecting female and male phenology, and reproductive synchronisation were studied. The between-year variation in the timing of flowering was more than three weeks. However, when it was defined on the basis of the effective temperature sum, the variation was smaller. No phenological reproductive isolation was found between the seed orchard and surrounding natural forests. The duration of the receptive period of the seed orchard varied from 5 to 8 days, and anthesis determined on the basis of airborne pollen from 5 to 10 days. The receptive period started about one day earlier than anthesis, except in one abnormally warm flowering period when female and male flowering started simultaneously. In general, the flowering periods of the different clones overlapped. The clonal differences in the phenology of receptivity were in most cases statistically significant, but in pollen shedding they were not. The broad-sense heritability estimates were higher for female than for male phenology. Environmental factors, conversely, had a stronger effect on male phenology. A wide graft spacing and a graft position that favoured solar radiation on the lower parts of the crown promoted early pollen shedding and, subsequently, better reproductive synchronisation between female and male flowering.

Citrus Mealybug (Homoptera: Pseudococcidae): Behavior of Males in Response to Sex Pheromone in Laboratory and Field

The copulatory behavior of the male citrus mealybug, Planococcus citri (Risso), encompasses a complex hierarchy of responses elicited by sex pheromone and possibly other cues. The male is an early morning flier with a flight range of at least 183 m. The male's morning activity is influenced by a scotophase period; flight and response to females were curtailed when exposed to 6 h of light before testing. The response of males to females was partially resumed when kept in constant light for > 24 h. In the field, male phenology was restricted to periods when monthly mean temperatures exceeded 5°C.