Determination of incompatibility genotypes in almond using first and second intron consensus primers: detection of new S alleles and correction of reported S genotypes

The work aimed to develop a reliable and convenient PCR approach for determining incompatibility S genotypes in almond. Initially, genomic DNAs of 24 accessions of known S genotype were amplified with novel consensus primers flanking the first and second introns of the S‐RNase gene. The PCR products separated on agarose showed length polymorphisms and correlated well with the reference alleles S1‐S₂3 and Sf. In addition, to improve discrimination between alleles of similar sizes, the same sets of primers but fluorescently labelled were used, and the products sized on an automated sequencer. These fluorescent primers were particularly informative in the case of the first intron, variation in the length of which has not been used previously for S genotyping in almond. Some reference alleles showed the same patterns with first and second intron primers, and others showed a microsatellite‐like trace. Subsequently, the S genotypes of 26 cultivars not genotyped previously and of four of uncertain genotype were determined. An allele described in Australian work as putative S₁₀ was shown to be a ‘new’ allele and ascribed to S₂₄ and evidence of five more ‘new’S alleles was found, for which the labels S₂₅‐S₂₉ are proposed. This PCR approach should be useful for genotyping in other Prunus crops.     

Genetics of Resistance to Phytophthora capsici in the Pepper Line 'SCM-334'

In order to establish a genetic model of the resistance to Phytophthora capsici in Capsicum annuum genotype ‘SCM-334’, two experiments were conducted which included ‘SCM-334’, as well as, the susceptible line ‘Morrón INIA 224’ and their Fl, F2, F3 and BC1 generations. We also tried to introgress a recessive gene, hypothetically responsible for resistance to P. capsici, from ‘SCM-334’ into ‘Morrón INIA 224’. Inoculations were made, when plants had 4—6 leaves, by irrigating the culture substrate with a zoospore suspension of P. capsici isolate ‘Bl’. The χ² test was applied to segregating generations to determine how many genes were involved in resistance. The hypothesis which explained the obtained segregations best, although not completely, was one that assumes 3 genes in ‘SCM-334’;, with at least 3 alleles in the heterozygous condition or 4 at any position, present in any genotype in order to be resistant. The influence of the isolate's aggressiveness and the inoculation method on the results are discussed.     

Self-pollination vs. cross-pollination in almond: pollen tube growth, fruit set and fruit characteristics

Pollen tubes reaching the ovary, fruit set and the main fruit characteristics of six self‐compatible genotypes (‘Marta’, ‘Antoñeta’, ‘Guara’, ‘Lauranne’, ‘S2332’ and ‘S4017’) of almond were studied after self‐ or cross‐pollination. No significant differences after self‐ or cross‐pollination were found in the number of pollen tubes reaching the ovary, the percentage of ovaries finally penetrated, fruit set and fruit characteristics. The results showed the possibility of obtaining suitable fertilization, yields and quality of fruits by self‐pollination of self‐compatible almond cultivars in a single cultivar orchard.     

The possibilities of early selection of late-flowering almonds as a function of seed germination or leafing time of seedlings

Obtaining new, late‐flowering almonds by crossing is a very long process, mainly due to the long juvenile period of the seedlings obtained. It would be very useful to have an early selection method to identify the late‐flowering genotypes, which would increase the efficiency of the breeding programmes. In this work, a study was made of the possibility of using the chilling requirements of seeds for germination and the leafing time of seedlings as criteria for early selection of flowering time, in 502 seedlings belonging to 13 families, over a four‐year period. Crossings were carried out in 1997. Seeds were stratified at 7°C. and the number of weeks necessary for germination was determined. Seedlings were planted in 1998. Between 1999 and 2002 the leafing time was recorded, and in 2001 and 2002 the time of flowering was also recorded. The results showed that, although some correlation was observed between the germination or leafing time and the flowering time, these correlations were not strong enough to be used as efficient criteria for early selection of late‐flowering seedlings within each family. for which variability was limited. To obtain late‐flowering cultivars. the best method is to cross progenitors which flower as late as possible, and later select the seedlings according to their flowering time. Leafing time could be used for early selection with certain success when progenitors have very different flowering times (VCTJ early and very late), since the expected variability within families will be very large.     

Beyond host specificity: the biotechnological exploitation of chitolectin from teratocytes of Toxoneuron nigriceps to control non-permissive hosts

Journal of Pest Science - The virulence factors (VF) that parasitoids use to regulate the growth and development of their hosts have potential as new events in transgenic plants. VFs are promising...     

The influence of fruit and vegetable intake on the nutritional status and plasma homocysteine levels of institutionalised elderly people

OBJECTIVE: To determine the difference in the nutritional status of elderly people depending on their consumption of fruits and vegetables, and to study the possible association between the consumption of these foods and different cardiovascular risk factors, especially total plasma homocysteine (t-Hcys) levels. DESIGN, SETTING AND SUBJECTS: A cross-sectional study in 152 institutionalised older people from Madrid aged > or = 65 years. Food and nutrient intakes were recorded over 7 days using the 'precise individual weighing' method. The weight, height, and waist and hip circumferences of all subjects were recorded, as were their alpha-erythrocyte glutathione reductase, serum B6, B12 and folate levels, erythrocyte folate levels, t-Hcys levels, serum lipids and blood pressure. The experimental population was then divided into tertiles depending on the serving intake of fruit and vegetables (T1, < 2.29 servings day(-1); T2, 2.29-2.79 servings day(-1); and T3, >2.79 servings day(-1)). RESULTS: Compared with T1 subjects, T3 subjects showed consumptions of cereals, pulses, meat, fish and eggs closer to those recommended (P < 0.05). In addition, the contribution of their diet towards covering the recommended daily intake of vitamin B1, niacin, vitamin B6, folic acid, vitamin C, B12, vitamin A, and P, Mg, Zn and Fe was higher. The intake of fibre increased with consumption of fruit and vegetables (r = 0.6839, P < 0.001). T3 subjects also had better serum and erythrocyte folate levels than T1 and T2 subjects (P < 0.05). A positive correlation was found between the consumption of fruit and vegetables and serum folate (r = 0.2665, P < 0.01) and with erythrocyte folate levels (r = 0.2034, P < 0.05), and a negative correlation with t-Hcys (r = -0.2493, P < 0.01). CONCLUSIONS: Greater consumption of fruit and vegetables is associated with better food habits, increased vitamin and mineral intakes and lower t-Hcys levels. Considering that the fruit and vegetable intake in Spanish elderly people is very low, it is recommended that the consumption of fruits and vegetables by elderly people be increased.