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Abstract

The genus Phoenix is characterized by dioecious wind-pollinated woody trees. The date palm (Phoenix dactylifera L.) is one of the world’s oldest cultivated fruit trees. The date palm inflorescence consists of a compound spadix enclosed by a spathe. Flowers are produced on strands. At anthesis, the spathe splits and the strands loosen and spread to expose the flowers. Cultivated date palms are artificially pollinated. Mature male inflorescences are cut off before the spathe splits, and the strands are placed in female flower clusters to ensure pollination. In earlier studies of pollen structure and stainability (1,2), abnormally large pollen grains were noted occasionally. This study dealt with pollen size distribution in 10 male palms used to pollinate female trees in commercial groves in the Al-Hassa region of Saudi Arabia.

Cacao (Theobroma cacao L.) is an important cash crop in tropical growing regions of the world and particularly for small cacao farmers. Over the past two decades, ‘CCN 51’ has become one of the most planted cultivars in Ecuador, mainly as a result of its high productivity and disease resistance. Intermixing of Nacional fine flavor Ecuadorian beans with beans of ‘CCN 51’ has become common practice, reducing overall bean quality and decreasing value. The primary goals of this study were to determine the genetic identity, structure, and allelic richness of ‘CCN 51’, its maternal origin and to compare ‘CCN 51’s’ agronomic characteristics against a composite group of Nacional cultivars. To investigate the complex genetic background of this cultivar, 70 simple sequence repeat loci were used. The high heterozygosity observed (56 of 70 loci) for ‘CCN 51’ is not characteristic of traditional Nacional cultivars. Comparison of agronomic characteristics between ‘CCN 51’ and several Nacional cultivars indicates significant differences in cacao dry bean weight, yield potential, production efficiency, percent healthy pods, and witches' broom [Moniliophthora perniciosa (Stahel) Aime & Phillips-Mora] disease incidence. Additionally, physical, chemical, and organoleptic characteristics suggest that ‘CCN 51’ is different from those of Nacional lineage. Based on population structure analysis, the predominant ancestries for ‘CCN 51’ are Iquitos (45.4%), Criollo (22.2%), and Amelonado (21.5%) genetic groups. A lesser proportion of its genome was accounted for by genetic groups Contamana (3.9%), Purús (2.5%), Marañon (2.1%), and Nacional (1.1%) admixtures. Results of phylogenetic analyses using the unweighted pair group method with arithmetic mean yielding high bootstrap values strongly support the relatedness of ‘CCN 51’ with Iquitos, Criollo, and Amelonado genetic groups. Moreover, seven mitochondrial simple sequence repeat loci revealed that ‘CCN 51’ maternally inherited the ‘IMC 67’ cytotype. ‘CCN 51’ constitutes a valuable cacao genetic resource that is currently used not only in its country of origin, but also in many other national breeding and selection programs worldwide.

There are three main systems for the removal of carbon dioxide (CO₂) from controlled atmosphere (CA) stores: activated carbon (AC) scrubber, hydrated lime scrubber, and nitrogen (N₂) flushing. Each system is likely to have a different effect on the accumulation of volatiles other than CO₂ in the store atmosphere, and these volatiles may influence the storage performance of the produce. `Hayward' kiwifruit (Actinidia deliciosa) were stored at 0 °C (32.0 °F) under 2% oxygen (O<sub>2</sub>) and 5% CO<sub>2</sub> in CA rooms fitted with one of the three systems. In a fourth CA room, fruit were stored at 0 °C under air conditions. All four stores had their atmosphere scrubbed for ethylene. The store atmospheres and fruit firmness were monitored at intervals up to 27 or 14 weeks of storage in the 1999 or 2000 season, respectively. At the end of CA storage, and after an additional 4 weeks of air storage at 0 °C, fruit were evaluated for rots and physiological pitting. Linear discriminant analysis (LDA) showed the three CO<sub>2</sub> removal systems altered the volatile profiles of the store atmospheres differently. CA storage delayed fruit softening markedly, and once returned to air, softening resumed at a rate equivalent to that of fruit of equivalent firmness that had not been CA stored. There was little effect of CO<sub>2</sub> removal system on the fruit softening during storage. Although CA storage resulted in a higher incidence of rots, there was little difference among CO<sub>2</sub> removal systems compared to the main effect between air and CA storage. Similarly, CA storage delayed the appearance of physiological pitting, although the incidence increased rapidly during an additional 4 weeks of storage in air, and was higher than for fruit stored throughout in air. Among the CO<sub>2</sub> removal systems, N<sub>2</sub> flushing resulted in fruit with the lowest incidence of physiological pitting. It is concluded that different CO<sub>2</sub> removal systems alter room volatile profiles but may not consistently affect the quality of `Hayward' kiwifruit during CA storage.