Search Results

You are looking at 1 - 10 of 111 items for :

  • carrot breeding x
Clear All

Abstract

Lines Oregon 4, 5, 6, and 14 carrot CDaucus carota L.) were released for breeding or further selection, after the Oregon State University breeding program was terminated in 1978. These lines were developed at Corvallis with consistent exposure to wet autumn weather and are considered to have useful resistance to cracking and rotting under such conditions. They are primarily for processing use, and have shown good quality when canned or frozen, with deep orange to red-orange color and little occurrence of green core.

Open Access
Author:

This experiment was carried out to breed promising brown anther type male sterile lines of carrots having the desirable characteristics of higher seed yield and stable phenotypic expression of male sterility. Brown anther type male sterile lines used for this experiment had been derived from the male sterile sources selected from the seed multiplication plots of Shin Kurota cultivar in 1972. Brown anther type male sterile lines are, in general, good seed yielders but frequently show unstable phenotypic expression of male sterility as compared to petaloid type male sterile lines. Through several years of selection for male sterile lines and plants, brown anther type male sterile lines with good seed-yielding potentials and stable phenotypic expression similar to petaloid type were developed. Outline of the breeding scheme, potential benefits of these newly bred MS lines, etc. will be discussed.

Free access

Abstract

Cultivars and breeding lines of carrot (Daucus carota L.) with established differences in sugar accumulation capacity were studied by growth analyses to identify associations of sugar content with other traits. Carrots were grown on both organic and sandy loam soils. At both locations the seasonal patterns for sugar content of a high sugar-accumulating cultivar/line (HSL) and a low sugar-accumulating cultivar/line (LSL) were similar. There was little or no association of growth indicators (dry weight accumulation, tap root dry weight, and leaf area index) with high or low sugar accumulation. Differences in sugar yields were associated with mean net assimilation rate ( NAR ¯ ), mean relative growth rate ( RGR ¯ ) and leaf area ratio (LAR) late in the growing season. The HSL had increasing ( NAR ¯ , RGR ¯ , and LAR, whereas LSL had decreasing NAR ¯ , RGR ¯ , and LAR late in the growing season. In general, carrot cultivars and breeding lines producing high free-sugar concentrations were distinguished from low sugar-accumulating carrots by delayed physiological maturity resulting in prolonged photosynthetic activity late in the growing season.

Open Access

Freezing stress resistance is composed of several components namely tolerance, avoidance and acclimation ability. These three components of freezing stress are heritable traits. We have demonstrated that progress in the improvement of freezing stress resistance can be made by individually selecting for various components of this resistance and then recombining them to get the desired plan. Freeze-thaw injury in carrots is manifested as damage to the foliage, cracks on the roots (especially on the crown), and crown root rot. We found that foliage damage following freeze-thaw stress was related to the tolerance of the foliage to ice formation. The formation of cracks in the crown and root tissue was related to formation of ice itself. The carrot breeding lines we tested varied considerably for the crown position in relation to soil surface. The carrot crowns and roots below the soil surface will be better in avoiding ice in the tissue, thus avoiding cracks. The freeze-thaw injury observed on the foliage in the field was highly correlated to the freeze-thaw tolerance of leaf tissue (measured as ion leakage from the leaf tissue) determined by controlled freeze-thaw test in the laboratory. Based on this work we developed a breeding strategy to improve frost hardiness in carrots by combining the characteristics that avoid ice in the crown and root tissues (e.g., crown position underground) with the characteristics that reduce foliage and root injury by ice (freezing tolerance of foliage). By using this strategy we were able to successfully obtain the desired plant. Two hardy carrot hybrids (Eskimo, Artico) were released by Vilmorin and their hardy characteristics have been confirmed under field conditions.

Free access

), and germination at sub- or supraoptimal temperatures may be a desirable trait for incorporating into carrot breeding programs. High genetic variability observed among progenies from the ‘Brasilia’ carrot group suggested that simple breeding methods may

Free access

both processing and fresh market carrot cultivars ( Just and Simon, 2004 ). More recently other important antioxidant compounds have been identified and enhanced in carrot germplasm, including anthocyanins and lycopene. The carrot breeding program at

Free access

Poster Session 53—Vegetable Breeding 2 21 July 2005, 1:15–2:00 p.m. Poster Hall–Ballroom E/F

Free access
Author:

`BetaSweet' is a new “designer” carrot that was conceived as a research project with the objective to create a new high-quality vegetable with unique characteristics. The gene responsible for purple or maroon color in carrots is a natural one and has been around for many years. Carrot breeders have discarded carrots which occasionally segregated to this color because orange has been the preferred traditional color. In 1989, three carrots grown from Brazilian seed were observed to have a blotchy maroon color mixed with the normal orange. Within two generations of breeding effort I had obtained a few carrot roots with near complete maroon exterior color and orange interior. The contrast of orange and maroon was very attractive in carrots cut as coins or sticks. The maroon and orange color would serve as the perfect way to identify and promote this new variety. Several additional generations were required using extensive laboratory testing for low terpenoids (strong carrot flavors), high sugars, high carotene, and crispy texture. Thousands of carrot roots were analyzed and selected for those qualities and for the dark maroon exterior and orange interior colors. The few best for those characteristics were intercrossed, and reselected for their adaptation when grown under Texas climatic conditions.

Free access