Efficiency of bunch-planted and single-planted seedlings for selecting superior families in sugarcane

Summary The efficiency of family selection in bunch-planted sugareane seedlings was investigated by planting 40 families (20 proven and 20 experimental) as bunches and as single seedlings in adjoining replicated trials. A replicated trial planted the following year. using stem cuttings from random seedlings of each family. provided an independant estimate of the value of each family.Five methods were used to compare bunch and single planting, namely theoretical and realized gains from selection, correlations between the seedling and evaluation trials, discrimination based on proven cross classes, and discrimination based on production of advanced selections. Overall, bunch planting was inferior to single planting for family selection. It was promising for only one method of evaluation (proven cross classes) but this, combined with the relatively small area required for bunch-planted seedlings, indicates that family selection may be possible in such plantings. The use of a number of methods of evaluation showed that incorrect conclusions were likely if only one method were used, and revealed deficiencies in methods which would otherwise be considered satisfactory. The project provided a basis for the design of more critical experiments.The components of weight of cane, namely number of stalks and weight per stalk, are negatively correlated, and showed different relationships with yield in the seedling and evaluation trials. Weight per stalk was an important component in seedling trials, with number of stalks by far the main component in the evaluation trial which was planted by the commerical method using stem cuttings.Family selection based on number of stalks and sugar content, preceding mass selection, is likely to provide a better selection system than the usual mass selection in bunch-planted seedlings.Families do not express their full genetic potential in original seedlings. whether bunch or single planted: trials planted from stem cuttings give more effective family selection. Furthermore, family selection for the most important characters (net merit grade and weight of sugar) was much more effective in ratoon than in plant crops. These results have important implications for the practical selection program, further experimental work being necessary to specify the most efficient system.     

Vegetative propagation of Beta vulgaris by leaf cuttings

Summary Leaf cuttings without axillary buds were made from young vegetative beet plants. Roots were formed at the petiole end. Adventitious bud formation occurred at a very low frequency and could not be stimulated by application of growth regulators. Leaf cuttings with axillary buds formed plants at a higher frequency but development of buds into shoots was slow and irregular. As no vascular connections were found between petiole and axillary bud, the slow growth of the buds was attributed to insufficient supply of assimilates from the leaves. Axillary buds rapidly developed into shoots when petiole explants with buds were placed on culture media. Nearly all cultures, however, were contaminated with bacteria that originated from the inner tissue of the explants.     

Solute Accumulation as a Cause for Quality Losses in Sugar Beet Submitted to Continuous and Temporary Drought Stress

Adaptation to low water availability in sugar beet includes the accumulation of solutes relevant for the technical quality of the beet. Two sugar beet genotypes were grown in pot experiments under drought stress of different severity to study effects on taproot composition and concentration of solutes relevant for technical quality, reversibility of drought effects after re‐watering and genotypic differences in drought response. Differences in stress sensitivity between the genotypes were not observed as reductions in taproot and leaf dry weight and white sugar yield were the same. Increasing dry matter concentration with decreasing water supply could, in part, be attributed to an increase in the concentration of cell wall components. The major solutes in the taproot were sucrose, potassium, amino N (the sum of amino acids) and betaine. Sucrose concentration decreased considerably under drought, indicating limited availability of assimilates. In contrast, all further solutes increased in concentration with increasing severity of stress. However, the response of individual solutes varied largely. Changes in amino N and nitrate were most pronounced and probably reflect accumulation of non‐utilized metabolites under limited growth. The drought‐induced accumulation of taproot solutes implicates a considerable decrease in the technical quality of the beet. It was only in part reversible by re‐watering. Genotypic variability for solute accumulation under water deficiency was observed but was not linked to drought tolerance.     

Major genes for resistance to beet necrotic yellow vein virus (BNYVV) in Beta vulgaris

Summary Inheritance of resistance to beet necrotic yellow vein virus (BNYVV) was studied in segregating F2 and backcross families obtained from crosses between resistant plants of the sugar beet selection Holly-1-4 or the wild beet accession Beta vulgaris subsp. maritima WB42 and susceptible parents. Greenhouse tests were carried out, in which seedlings were grown in a mixture of sand and infested soil. Virus concentrations of BNYVV in the rootlets were estimated by ELISA. To discriminate resistant and susceptible plants, mixtures of normal distributions were fitted to log₁₀ virus concentrations, estimated for segregating F1, F2 and BC populations of both accessions. The hypothesis that Holly-1-4 contained one single dominant major gene was accepted. For WB42, results fitted with the hypotheses that resistance was based on either one (or more) dominant major gene(s) showing distorted segregation, or two complementary dominant genes, which are both required for resistance. Resistance from WB42 appeared to be more effective against BNYVV than resistance from Holly-1-4.This research was carried out as part of a PhD study at the Graduate School Experimental Plant Sciences (EPS), Department of Virology, Wageningen, The Netherlands     

Inter-relationships among cane yield and commercial cane sugar and their component traits in autumn plant crop of sugarcane

Seventeen diverse clones of sugarcane (Saccharum spp.) (7 early, 6 mid season and 4 late) were planted in October 1991 and 1992 in flooded (FE) and non flooded (NFE) environments for evaluation of cane yield, commercial cane sugar (CCS), internode length, internode number, stalk length, stalk thickness (circumference), stalk number, sugar recovery, and stalk weight. Cane yield showed significant positive phenotypic correlation coefficient (PCC) with stalk number in FE (P ≤ 0.05) and NFE (P ≤ 0.01). Stalk length had a significant positive PCC with stalk weight in both environments, and with internode length in FE (P ≤ 0.05). Commercial cane sugar also expressed significant positive PCC with cane yield in both environments (P ≤ 0.01), but with stalk number only in NFE (P ≤ 0.05). Genotypic correlation coefficients were generally in the same direction as PCC but higher in magnitude. In both environments, stalk number and stalk weight had relatively high positive direct effects on cane yield. However, flooding tended to enhance the direct effect of stalk weight and diminish the direct effect of stalk number on cane yield. Only cane yield and sugar recovery had high direct effects on CCS. Selection for improvement of cane yield can be based on stalk number and stalk weight in both environments. High yielding clones can be further screened for more sugar recovery to improve CCS. This revised version was published online in July 2006 with corrections to the Cover Date.     

New Genetic Markers in a Wild Species of Beet (Beta nana Boiss. et Heldr.): Prospects for Utilization

In a study of variation in 13 enzymes occurring in B. nana, unique and invariant phenotypes were found for five of these enzymes, when compared with a range of other wild and cultivated beets. In similar comparisons unique alleles were found in B. nana for two other enzyme loci. For the remaining six enzymes B. nana was found to have variation and alleles which were common to other forms of beet. It is concluded that reliable markers for B. nana exist, and that this species represents a source of novel genes for sugar beet breeding.     

Genetic study of bolting and stem length in sugar beet (Beta vulgaris L.) using a factorial cross design

Summary The objective was to study the genetic basis of bolting and stem length in sugar beet full-sibs, developed by a factorial mating design (N.C. design II). The extent to which the inheritance of these characters can be attributed to the additive and non-dominance variation was investigated. The genetic analysis consisted of three sets (4×10, 4×8, and 3×8) of progenies. Estimates of additive genetic variance (² _A) and variance due to dominance deviations with some fractions of epistatic variance (² _D) were obtained for both characters. Bolting had a relatively large proportion of total genetic variance accounted for by ² _A. In most cases, non-additive effects were also important in determining the type of gene action in bolting. Stem length showed similar genetic variation to bolting susceptibility. Bolting resistance seemed to be dominant to the bolting susceptibility in most cases. Narrow sense heritability estimated for bolting was generally very large (0.93 to 0.96), which suggests that early generation selection for bolting resistance in a sugar beet population would be successful.     

不同处理对蘑菇与黄豆芽混合汁营养成分的影响

采用不同工艺条件测定蘑菇与黄豆芽混合汁中营养成分的含量。经测定得知,蘑菇：黄豆芽：水：1：2：3,利用内源酶水解24h,混合汁中水溶性含氮物、VC含量较高,利用内源酶或盐酸水解可显著提高还原糖浓度。     

Modification of sugar profiles in California adapted apricots (Prunus armeniaca L.) through breeding with Central Asian germplasm

Summary Central Asian apricot germplasm was used in hybridizations with California adapted apricots to increase Brix levels and improve fresh eating quality. Fruit from parental trees, the F₁ hybrid and two backcross families were evaluated for fruit quality traits and analyzed by HPLC for specific sugar content. The F₁ hybrid between Central Asian and California adapted apricots was intermediate to its parents in many of the evaluated characteristics and levels of specific sugars. When the F₁ hybrid was backcrossed to California adapted apricots ‘Lorna’ and ‘Robada,’ the resulting hybrids were diverse in Brix, juice acidity, fruit size and profiles of specific sugars. Glucose: fructose ratios higher that 3.3 were encountered in fruit from five of the 22 analyzed seedlings, and fructose: sorbitol ratio ranged from 0.67 to 6.46. Brix and total sugar content correlated significantly with each other and with both sucrose and glucose. No significant correlations existed between sorbitol and any of the other analyzed sugars, nor with Brix or total sugars. The results demonstrated the extent of sugar profile modification possible in California adapted apricots after just two generations of breeding with Central Asian apricot germplasm.     

栎属4个树种秋冬叶色与生理变化的关系

为了研究栎类树种秋冬转色期叶色变化的生理机制,以栎属4个树种——鲜红栎(Quercus coccinea)、纳塔栎(Quercus nuttallii)、沈氏栎(Quercus shumardi)、针栎(Quercus palustris)为试材,测定其秋冬转色期叶绿素、类胡萝卜素、花色素苷3种色素和可溶性糖、可溶性蛋白质含量变化。结果表明:叶绿素a、叶绿素b、总叶绿素含量均呈先快后慢的下降趋势;类胡萝卜素含量鲜红栎和沈氏栎呈现下降-上升-下降的趋势,其他2个树种呈平缓下降的趋势;花色素苷含量呈波动上升趋势;叶绿素a与叶绿素b的比值变化趋势前中期较为平缓,后期迅速下降;鲜红栎的可溶性糖含量为单峰曲线,其他3个树种呈双峰曲线,与花色素苷相关性不显著;蛋白质含量与花色素苷含量呈正相关。