White-flowered Cultivars Research Articles

Inheritance of yellow-flowered characteristic and yellow pigments in diploid cyclamen ( Cyclamen persicum Mill.) cultivars

The mode of inheritance of the yellow-flowered phenotype of yellow-flowered cyclamen was investigated. All F 1 progenies obtained by reciprocal crosses between yellow- and white-flowered cultivars were white-flowered and did not contain chalcone, the main pigment of yellow-flowered cyclamen. The segregation ratio of flower colors in most of F 2 and BC 1 progenies fitted the expected Mendelian ratio, showing that the yellow-flowered phenotype was controlled by a single recessive gene. The petals of all yellow-flowered plants in F 2 and BC 1 progenies contained chalcone. It is suggested that a single recessive gene causes the lack or defectiveness of chalcone-flavanone isomerase and determines the yellow-flowered phenotype.

FEEDING PREFERENCES OF THE WESTERN FLOWER THRIPS, FRANKLINIELLA OCCIDENTALIS (PERGANDE) (THYSANOPTERA: THRIPIDAE), AND INCIDENCE OF TOMATO SPOTTED WILT VIRUS AMONG CULTIVARS OF FLORIST’S CHRYSANTHEMUM

AbstractA wide range in feeding damage as defined by leaf scars among 27 cultivars of florist’s chrysanthemum was apparent for the western flower thrips, Frankliniella occidentalis (Pergande). Assessments based on numbers of feeding scars or ranking of cultivars on the basis of the leaf area damaged by feeding were in close agreement. Cultivars with the most feeding damage under growth room conditions, such as cvs. White Marble and Polaris, were the same as those in plots within a naturally infested commercial greenhouse. Under growth room conditions, a 2- to 4-week exposure of plants to a population of thrips was sufficient to evaluate feeding damage. Closely related cultivars had similar levels of feeding damage, and foliage of yellow-flowered cultivars was significantly more attractive to thrips for feeding than foliage of white-flowered sister cultivars during the pre-bloom period. There was a low correlation between feeding damage and incidence of the tomato spotted wilt virus among cultivars in both growth room and greenhouse tests, indicating that virus susceptibility of cultivars was epidemiologically more significant than the feeding activity of western flower thrips.

The nutritive value of white- and dark-flowered cultivars of pea for growing-finishing pigs

The nutritive value of two white- and one dark-flowered cultivar of pea was determined in eight growing pigs weighing 31–55 kg. Each diet was given to two animals according to a replicated 4 × 4 Latin Square design. The apparent digestibility coefficients of organic matter, neutral detergent fibre, crude fibre and energy were significantly lower ( P < 0.05) for the dark-flowered cultivar than for the white-flowered cultivars. All pea cultivars differed significantly with respect to the digestibility of crude protein, whereas the dark-flowered cultivar had considerably lower digestibility coefficients than the other cultivars. The mean content of metabolizable energy in the dark-flowered cultivar was only 13.6 MJ kg −1 of dry matter, which was 1.5–2.1 MJ less than the contents of the two white-flowered cultivars. The differences in nutritive value between the white- and the dark-flowered cultivars of pea can be explained by a higher content of tannins and other “anti-nutritional factors” in the latter cultivar, which results in low digestibility of nutrients and energy and consequently, a lower content of metabolizable energy in the feed. The apparent digestibility coefficient of nutrients and energy and the metabolizable energy content of the diets increased with increasing weight and age of the animals. This is probably due to increased fermentation activity in the caecum-colon, as the efficiency of N retention and NPU were not influenced by changes in live weight.