Internal tipburn in white cabbage I. Variety trials

1. 1.
   In a number of variety trials with white cabbage observations on the occurrence of tipburn were made. The various varieties showed different degrees of susceptibility. Of the Dutch autumn varieties, Succes and Glory of Enkhuizen were little susceptible, whereas Langedijker Autumn White was highly susceptible. Between the strains of the latter variety there were clear differences in this respect.     
   
   

Inheritance of resistance to tipburn in cabbage

Summary Tipburn resistance was identified as being highly but not completely dominant in three nearly isogenic populations of cabbage. Narrow sense heritability estimates of 0.14, 0.34, and 0.49 and broad sense heritability estimates of 0.64, 0.74, and 0.77 were obtained with 2–4 genes controlling resistance. Analysis of resistance was made under conditions of high fertility, especially high N and plentiful moisture and generally high humidity which together resulted in very severe tipburn in susceptible plants.Journal Paper No. 3038 of the New York State Agricultural Experiment Station, Geneva, New York, USA.     

Resistance to turnip mosaic virus in white cabbage

Summary Resistance in white cabbage to external necrosis caused by turnip mosaic virus had a significant genetic component. Estimates of heritability ranged from 41% to 48%. Resistance to internal necrosis was determined by unknown environmental factors with no significant genetical component. Although correlation between external and internal symptoms was poor in general, plants which had no external symptoms at harvest did not develop internal symptoms during storage. It is proposed that selection for lack of external symptoms will also produce lines resistant to internal symptoms.     

Determination of the critical nitrogen concentration of white cabbage

A measure of a crop's nitrogen (N) status can be obtained by relating the actual N concentration of the crop to the critical plant nitrogen concentration (PNC_c), the minimum N concentration required for maximum growth. In annual crops, PNC_c declines as plant size increases. Describing this decline is one of the main challenges for the implementation of the PNC_c concept in fertilizer management strategies. From two field experiments with repeated harvests of Dutch white cabbage and with N supply ranging from limitation to excess, the relation between PNC_c and weight per unit ground area of plant dry matter exclusive of roots (W) was estimated as: PNC_c = 5.1W^−0.33% for the linear growth phase (W > 1.5 t ha⁻¹; LAI > 1.4). From a third field experiment, a value of 4.5% N was estimated for PNC_c for the pre-linear growth phase. Also a power function: LAR = 0.011W^−0.33 described the relationship between leaf area ratio and weight. The exponent of the power function determines the rate of the decline. Therefore, having the same value of the exponent: −0.33, LAR and PNC_c declined at the same rates. The proportional decline in LAR and PNC_c corresponded to a constant nitrogen content on a leaf area basis of 4.7 g N m⁻² until onset of head formation.     

Microspore culture of white cabbage, Brassica oleracea var. capitata L.: Genetic improvement of non-responsive cultivars and effect of genome doubling agents

For the efficient application of haploid induction procedures in cabbage breeding, a sufficient number of regenerants should be achieved in a broad spectrum of genotypes. However, the majority of genotypes are somewhat recalcitrant. The efficiency of microspore culture was tested by crossing a responsive (28.7 embryos per Petri dish) and a non- responsive (0.1 embryo) cabbage cultivar. The embryo yield of one progeny was intermediate (18.9) while two were superior to the best parent cultivar (52.9 and 64.0 embryos). Thus, genes for haploid embryogenesis, present in responsive lines, can be effectively transmitted to responsive × non-responsive hybrids. Abscisic acid-induced desiccation of embryos was used for the efficient regeneration of plants. High germination percentages (54.7-70.6%) followed by normal plantlet development were achieved. Spontaneous genome doubling measured at the plantlet stage differed markedly in untreated genotypes. The percentage of diploids ranged from 21 to 67%. The effects of two antimitotic drugs applied to freshly isolated microspores were determined in two experiments. In the first experiment, trifluralin (0.5 and 1.0 mg:l) had no effect on embryo induction while oryzalin partly (0.125-0.25mg/l) or completely (0.5.mg/l) inhibited the formation of embryos. In the second experiment, higher concentrations of trifluralin increased the proportion of diploidized plants. Application of anti-mitotic drugs to microspores did generally not improve the overall production of haploid plants, which was higher in an untreated control.     

Effect of Ogura male-sterile cytoplasm on the performance of cabbage hybrid variety. II. Commercial characteristics

Summary The main constraint of using Ogura male-sterile cytoplasm in Brassica is the induction of leaf yellowing at low temperature and the low seed set. But whether or not the cytoplasm can disturb the general commerical performance of the plants is not well-known. Therefore, this work was carried out with the purpose of evaluating Ogura cytoplasmic male-sterile cabbage hybrids and compare them to genomic similar male-fertile ones and to the most popular cabbage hybrid cultivated in Brazil. Harvest data showed an effect of the cytoplasm on reducing plant and head weight, core length and head length and width, although not altering heading index, shape and core indexes, nor head compactness. On the other hand, it was observed also that a careful selection of the parental lineages can produce male-sterile hybrids as good as their male-fertile analogues. All the evaluated hybrids were similar or better than the check for the characteristics under study.Abbreviations dat - days after transplanting - CNPH - National Center for Vegetable Crops Research     

Effect of mass selection in nil-competition conditions on some traits of four cabbage populations

Mass selection with controlled pollination for heading, resistance to early bolting, fewer frame leaves relative to head size and few cover leaves, was applied for three cycles in four Greek open‐pollinating populations (OPPs) of cabbage in nil‐competition conditions (honeycomb method). The cycle 0 OPPs with their respective cycle 3 OPPs were tested under competition conditions (growers density), in two successive years, to assess the selection response for heading, resistance to early bolting, number of cover leaves and yield. In most cases, the selection response was significant at P = 0.01 or even at P = 0.001. For example, the mean increase of yield estimated over all OPPs across 2 years was 36%, without any undesirable changes in dry matter and soluble solids contents.     

Hybrid breeding in early spring cabbage (Brassica oleracea var. Capitata L. F. Alba D.C.). II

Summary In diallel crosses of Io plants of pointed headed cabbage a significant sca variance for head weight and a significant gca variance for earliness was found.In a diallel set of inbred lines the sca variance for plant weight decreased when plants were harvested later, while the gca variance increased. By means of the Hayman-Jinks analysis clear overdominance but no epistatic effects could be recorded.Double crosses and mass propagated single crosses were inferior compared with single crosses and proved to be not attractive for horticultural practice.Already in a young plant stage differences in plant weight between inbred and hybrid plants were noted in favour of the latter. During the growth period this difference increased. Single crosses produced relatively fewer outer leaves than double crosses and inbred lines.     

The somatic karyotype of cabbage (Brassica oleracea ssp. capitata)

Summary The individual chromosomes of cabbage are identifiable in nucellar cells found in the ovaries of immature pistils by the combination of their relative length, arm ratios, secondary constrictions, chromatic and achromatic regions and the presence of satellites.     

Cross-fertilization behaviour of some white flowering varieties of Vicia faba

Summary Applying a special design for maximalization of cross-fertilization and using flower colour as a marker, considerable differences in the percentage of cross-fertilization between white flowering Vicia faba varieties were observed. Part of these differences were due to differences in beginning of flowering in white and coloured varieties, part of them proves to be independent of this and, therefore appear to be characteristic for the variety. Interaction between mother and father varieties was absent.     

Transfer of resistance to race 2 of Plasmodiophora brassicae from Brassica napus to cabbage (B. oleracea var. capitata). II. Meiosis in the interspecific hybrids between B. napus and 2x and 4x cabbage

Summary Meiosis in 14 interspecific F₁ hybrids with three chromosomal levels (triploid, tetraploid, hexaploid; 2n=28, 37 and 55) between Brassica napus L. and 2x and 4x cabbage (B. oleracea var. capitata L.) was studied. The oleracea genome from B. napus maintained close homology with the c genome of cabbage while the campestris genome of B. napus showed partial homology with the c genome contained in the hybrids. Genotypic influence on chromosome pairing was indicated. Structural chromosome differences and spontaneous chromosome breakage and reunion were suggested as causes for the abnormalities which related to the unbalance of the genotypes. The divergence of the genomes of B. napus and B. oleracea and the need for the qualification of the term secondary association were discussed.Contribution No. J. 673, Research Station, Agriculture Canada, St. Jean, Québec.     

Development and bioassay of transgenic Chinese cabbage expressing potato proteinase inhibitor II gene

Lepidopteran larvae are the most injurious pests of Chinese cabbage production. We attempted the development of transgenic Chinese cabbage expressing the potato proteinase inhibitor II gene (pinII) and bioassayed the pest-repelling ability of these transgenic plants. Cotyledons with petioles from aseptic seedlings were used as explants for Agrobacterium-mediated in vitro transformation. Agrobacterium tumefaciens C58 contained the binary vector pBBBasta-pinII-bar comprising pinII and bar genes. Plants showing vigorous PPT resistance were obtained by a series concentration selection for PPT resistance and subsequent regeneration of leaf explants dissected from the putative chimera. Transgenic plants were confirmed by PCR and genomic Southern blotting, which showed that the bar and pinII genes were integrated into the plant genome. Double haploid homozygous transgenic plants were obtained by microspore culture. The pinII expression was detected using quantitative real time polymerase chain reaction (qRT-PCR) and detection of PINII protein content in the transgenic homozygous lines. Insect-feeding trials using the larvae of cabbage worm (Pieris rapae) and the larvae of the diamondback moth (Plutella xylostella) showed higher larval mortality, stunted larval development, and lower pupal weights, pupation rates, and eclosion rates in most of the transgenic lines in comparison with the corresponding values in the non-transformed wild-type line.     

安徽不结球白菜地方种质资源概况

安徽省自南向北跨中亚热带、北亚热带和暖温带,气候复杂多变,主要特征为季风明显、四季分明、春温多变、梅雨显著.年平均气温在14℃～18℃之间,由北向南递增,南北相差近3℃.年平均降水量700～1700mm,从南向北递减.由于气候条件和复杂多样的地形地貌,安徽省的蔬菜种质资源极为丰富,不结球白菜地方品种繁多,自"七五"以来,我们共在全省征集不结球白菜地方种质资源116份,现将安徽不结球白菜种质资源概述如下.     

圆白萝卜周年均衡供应无公害栽培技术

盐城市萝卜栽培历史悠久，由于得天独厚的自然条件，生产的萝卜肉质脆嫩，水分多，口感好，外皮光滑，深受消费者欢迎。近年来，盐城市萝卜生产发展迅速，２００１年种植面积达８０００hm２，种植方式由过去的每年１季发展到周年栽培（每年５季），产量由过去的每６６７m２年产     

Broccoli yield response to environmental factors in sustainable agriculture

A reduced rank factorial regression was carried out to assess effects of environmental factors in sustainable agriculture on yield performances of homogeneous (one F1 hybrid) and heterogeneous (one landrace, LR, and two derived synthetics) broccoli varieties under Organic Agriculture (OA) and Low-Input (LI) management systems. The study was motivated by a general lack of data on environmental variables that affect broccoli yield. Agronomic trials were carried out for three years in three locations in Central Italy with different pedo-climatic conditions. Reduced rank factorial regression was efficient in summarising the effect of environmental variables on the pattern of Genotype (G) × Environment (E) interactions.Nitrogen content, together with rainfall, minimum temperature and clay content, were the most important environmental variables and explained 91% of the variability in the G × E interaction matrix. A mild and nitrogen-rich environment allowed good performances to be achieved with all genotypes and maximised the F1 hybrid yield. The synthetic varieties and the LR tolerated a high clay content, even though broccoli crops prefer, in general, alluvial, deep and permeable soils without water stagnation. This suggests that the above mentioned varieties are the best materials for these yield-limiting environments, possibly because they were selected under those conditions.The results highlight the needs (i) to carry out further agronomy research aimed at identifying the most suitable areas and optimizing the control of environmental variables in OA and LI (in particular, type, quantity and time of application of N fertilization), (ii) to develop specific breeding programs for OA and LI and, while carrying them out, (iii) to evaluate the responses of the genotypes under selection to limiting environmental variables.     

春白菜露地栽培品种比较试验

延庆县露地栽培春白菜品种比较试验表明：品种春泉F1在植物学性状、产量、商品性、抗病性、品质等方面均表现最佳，春宝黄、旺春、健春的综合表现虽不及春泉F1，但各有优点、适应性较好，且产量、抗病性及商品性均好于对照品种强势。     

The effect of interplant distance on the effectiveness of honeycomb selection. II. Results of the second selection cycle

Summary For a second consecutive generation, the efficiency of the honeycomb selection procedure was observed at low and at high density, i.e. interplant distance being 100 cm and 15 cm respectively. Progress due to selection was determined for each of the two plant densities applied by comparing the performance of offspring from selected plants with that of offspring from plants taken at random. The relation between selection intensity and selection response was observed to study the relation between competing and yielding ability in presence and in absence of interplant competition.Compared to results obtained in a previous generation, it is now dared to be more positive about the perspectives of selection in absence of interplant competition. It is tentatively concluded that single plant selection for yield at wide spacing gives a higher progress and allows a better identification of outstanding genotypes. However, the superiority of selection at low density is not confirmed neither by any estimator of a quantitative genetic parameter nor by the correlation between single plant yield and plot yield of their offspring. The disturbing factors found already in the former generation, namely variation in seed quality and a biased sample of random plants, exerted a less important role in the estimation of the progress. Nevertheless, it is believed that only when they can be reduced more reliable results can be achieved.     

Inheritance and selection of some fruit characters of apple. II. The relation between leaf and fruit pH as a basis for preselection

Summary The leaf pH of two year old apple seedlings was found to be sufficiently related to the fruit pH, measured when the seedlings were six to seven years old, to serve as a basis for pre-selection. Discarding all seedlings with an above average leaf pH (40% of the total) eliminated the majority (74%) of seedling with low-acid cum sweet fruits. The method was not effective for reducing the proportion of seedlings with high-acid cum sour fruits.