Kale Cultivars Research Articles

Overexpression of the glucosyltransferase gene BoaUGT74B1 enhances the accumulation of indole glucosinolates in Chinese kale

Glucosinolates are a diverse class of secondary metabolites that play a vital role in the plant defense response. Here, we investigated the function of the UDP-glucosyltransferase 74B1 (UGT74B1) gene in glucosinolate biosynthesis in Chinese kale. A 1401 bp coding sequence of BoaUGT74B1 was cloned from Chinese kale cultivar ‘Sijicutiao’. Among different organs, BoaUGT74B1 has the highest expression level in young seeds. Among different flower tissues, BoaUGT74B1 has the highest expression level in the pistil; the gene was downregulated in flower tissues as flowers matured. Subcellular localization showed that BoaUGT74B1 is located in chloroplasts. A purified ~50 kD fusion protein was obtained from Escherichia coli after prokaryotic expression of BoaUGT74B1. BoaUGT74B1 introduced into the white-flower cultivar ‘Sijicutiao’ and yellow-flower cultivar ‘Fuzhouhuanghua’ of Chinese kale by Agrobacterium-mediated transformation was strongly in both cultivars. Expression levels of BoaUGT74B1 in the overexpressed plants ‘Sijicutiao’ and ‘Fuzhouhuanghua’ were 1.53- to 2.93-fold and 3.07- to 5.30-fold higher, respectively than that of the wild type; the total indole glucosinolate content in these two overexpressed plants was 1.30- to 7.11-fold and 2.13- to 4.44-fold higher, respectively, compared with that in wild-type plants. Each indole glucosinolate accumulated in significant amounts in all overexpressed plants; 4‑methoxy glucobrassicin enhanced most in ‘Sijicutiao’ overexpressed plants, in concentrations up to 12.14-fold higher than the control; glucobrassicin enhanced most in ‘Fuzhouhuanghua’ overexpressed plants, reaching levels 22.76x that of its wild-type counterpart. Therefore, these findings indicate that BoaUGT74B1 plays an important role in the accumulation of indole glucosinolates in Chinese kale, and suggest the possible usefulness of this gene to improve the nutritional quality and resistance against biotic stress of Chinese kale.

Reaching the highest shelf: A review of organic production, nutritional quality, and shelf life of kale (Brassica oleracea var. acephala)

Societal Impact StatementSince its inception in the early 20th century, organic agriculture has grown increasingly popular due to its focus on a holistic, environmentally friendly approach to crop production. However, it is comparatively limited in biomass production, disease management, nutritional quality, and postharvest treatment compared to conventional agriculture. These challenges carry over into kale production, the majority of which is certified organic. This article reviews organic kale production, morphology, and shelf life, focusing on nutrition and plant breeding. It explores the shortcomings of organic output and potential areas of study to enhance shelf life in organic kale while maintaining nutritional quality. Summary Organic production has grown exponentially over the past few decades in both acreage and popularity worldwide. This review focuses specifically on kale produced in the USA. However, regulations limiting synthetic inputs leave organic produce at a disadvantage compared to conventional agriculture in terms of biomass, nutritional quality, disease management, and postharvest treatment. Organic agriculture requires significant improvements to be a viable means of production for a growing population. Kale (Brassica oleracea var. acephala) is a “nutritional powerhouse” leafy green vegetable. The high concentration of vitamins, minerals, and prebiotic carbohydrates in a low‐calorie food makes kale an important crop for combatting obesity‐related non‐communicable diseases. However, the short shelf life of organic kale and inevitable fresh food waste make developing new kale cultivars with increased shelf life essential. This review article aims to (a) review kale morphology, consumer preference, and production, and (b) review nutritional quality, its effect on shelf life, and current breeding efforts of kale. Future research could focus on developing a kale breeding pipeline following suitable kale germplasm selection adapted to organic agriculture with both superior shelf life and improved nutritional quality.

Investigation on the Relationship between Morphological and Anatomical Characteristic of Savoy Cabbage and Kale Leaves and Infestation by Cabbage Whitefly (Aleyrodes proletella L.)

The cabbage whitefly (CW), Aleyrodes proletella (L.) (Hemiptera: Aleyrodidae), is an important pest in Brassica oleracea L. crops. Little is known about the mechanisms of resistance to CW of savoy cabbage and kale cultivars. Light microscopy (LM) and scanning electron microscopy (SEM) analysis were used to determine the relationship between the morphological and anatomical features of savoy cabbage (Brassica oleracea L. convar. capitata (L.) Alef. var. sabauda L.) and kale (Brassica oleracea L. convar. acephala (DC.) Alef. var. sabellica L.) leaves and host suitability to colonization by CW. Two kale cultivars, “Redbor” and “Starbor”, and two savoy cabbage cultivars, “Gloriosa” and “Alcosa”, that differed in the degree of infestation by A. proletella were taken for histological analysis. The lowest infestation by all forms of A. proletella was observed on savoy cabbage cultivar “Alcosa” and kale cultivar “Starbor”. The reduced colonization by cabbage whitefly may be related to the structure of the epidermis and the anatomical features of the leaf. The leaves of “Starbor” and “Alcosa” had more folds in the epidermis, less numerous but larger stomata, and a more compact mesophyll structure compared to “Redbor” and “Gloriosa”. In both analysed species, there was no clear relationship between the thickness of the abaxial epidermal layer, thickness of the lamina, number of vascular bundles, and degree of infestation by the cabbage whitefly. This study identified promising sources of resistance to A. proletella among cultivars of savoy cabbage and kale. Varying infestation by CW was associated with morphological and anatomical characteristics of leaves. Further study is needed to confirm the relationship between insect resistance and leaf surface and morphological characteristics of leaves in a broader range of Brassica spp.

Electric stimulation promotes growth, mineral uptake, and antioxidant accumulation in kale (Brassica oleracea var. acephala)

Several studies have demonstrated that electric treatment has a positive effect, respectively, on germination, root growth and post-harvest quality. Nevertheless, there is still a lack of research on the effect of electric treatment on growth characteristics and quality of whole plants. Here, we explored the effect of electric fields on two cultivars of kale (Brassica oleracea var. acephala). Three levels of electric current (10, 50, and 100 mA) were applied to the nutrient solution of hydroponically grown plants for three weeks. Kale plants subjected to the electric fields, particularly 50 mA, had higher fresh and dry weights than the control. The absence of an electric field in a Faraday cage caused a significant decrease in shoot and root growth compared with the natural electric field (control). Electrostimulation enhanced nutrient uptake by activating root hair formation and active ion transport. Plants grown under 50 mA contained 72% more calcium, 57% more total phenolic compounds, and had a 70% greater antioxidant capacity than the control. This work provides foundational information regarding the effects of electrical stimulus on plants, which could enable the development of innovative culture technologies to improve crop yields and quality.

Multilocational Evaluation of Growth and Antioxidant Content of Curly Kale (Brassica oleracea L. var acephala) and Chinese Kale (Brassica oleracea var. alboglabra) in Sri Lanka

Curly kale (Brassica oleracea var. acephala) and Chinese kale (Brassica oleracea var. alboglabra) are cruciferous vegetables, which have recently gained great popularity in the world as a ‘superfood’. Generally, kale has the capacity to tolerate diverse climatic conditions while demanding fewer inputs, thus making it possible to cultivate them with a minimum cost for crop management. However, kale is still not widespread in Sri Lanka as a vegetable. Therefore, it has not been a commercialized crop to date. This study was conducted to explore the potential for cultivating kale in Sri Lanka. Two cultivars of curly kale (‘Dwarf green curled’ and ‘Winterbor F1’) and Chinese kale were cultivated in three agro-climatic zones representing three main climatic zones in the country, namely the Mid-Country Wet Zone, Mid country Intermediate Zone and Low-Country Dry Zone, using three different media (M1: Existing soil in each location; M2: Sand and coir dust mixture – ratio 1:1; M3: Sand, coir dust, and soil - ratio 1:1:1) at each location. The experiment was carried out as a three-factor factorial with three replicates as a pot experiment. Based on the present study results, even though all the varieties displayed a significantly (p < 0.05) higher growth in terms of dry matter accumulation in the Wet Zone, the growth in the other two locations was also found to be satisfactory. Dry matter accumulation was not significantly different among the varieties within each location. Different media did not have a significant influence on growth. Even though the antioxidant contents in all varieties varied among locations, the values were within the acceptable range. Therefore, both curly kale and Chinese kale can be successfully grown in the tested locations in Sri Lanka and can be easily introduced to local consumers as a ‘superfood’.

Genetic variation in the prebiotic carbohydrate and mineral composition of kale (Brassica oleracea L. var. acephala) adapted to an organic cropping system

Kale is a nutrient-rich leafy green that is mostly grown in conventional agricultural systems. The demand for organic kale has increased in the U.S.; however, cultivars bred for conventional production are not suited to organic production in terms of yield and nutritional quality. The objective of this study was to evaluate the genetic variation in biomass, prebiotic carbohydrates, and minerals of 18 commercial cultivars and 35 PI accessions of kale adapted to the organic system. Significant genetic variation in both prebiotic carbohydrates and minerals was noted in both kale cultivars and PI accessions. In the kale cultivars, leaf biomass ranged from 41.4–271.2 g/plant, with kale cultivar “Frizzy Joe” being the highest and “Fizz” the lowest. A single 100-g serving from these kale cultivars provides mineral micronutrients (20–314 mg K; 95−539 mg Ca; 20−67 mg Mg; 13−87 mg P; 0.4−3.1 mg Fe; 0.3−0.9 mg Zn; 0.4−1.9 mg Mn; 20−1030 μg Cu; and 0–940 μg Se) and prebiotic carbohydrates, including sugar alcohols (1.7–26.9 mg), simple sugars (0.03–334 mg), and raffinose and fructooligosaccharides (0–11.2 mg). Compared to the commercial cultivars, the kale accessions had higher concentrations of minerals, except for magnesium (Mg) and manganese (Mn), and prebiotic carbohydrates, except for sucrose and verbascose + kestose. In the commercial cultivars, heritability estimates for prebiotic carbohydrates and minerals were relatively low except for sugar alcohols, Mg, and zinc (Zn). In the kale accessions, heritability estimates of glucose, fructose, potassium (K), and selenium (Se) were high. Overall, significant genetic variation exists among kale commercial cultivars and germplasm for prebiotic carbohydrates and minerals, indicating the nutritional quality of kale in organic production can be further improved by germplasm selection.

Integrated management protocol for New Zealand endemic wheat bug (Nysius huttoni) in forage brassicas

Wheat bug, Nysius huttoni, is considered as an economic pest of forage Brassicas and many other cultivated crops, such as wheat, kale, and vegetables in New Zealand. Insecticides- as seed coatings and sprays are frequently used to manage this pest, but a high proportion of these insecticidal compounds enter the soil and leads to pesticide resistance, and they may impact beneficial arthropods and soil microorganisms, creating an adverse effect on ecosystem services (ES). In this paper, we discuss a technology, that we have developed to trap , for example, wheat bug away from kale seedlings, and integrating these in less susceptible kale cultivars that can potentially reduce over-reliance on orthodox pesticides on brassicas. Laboratory studies were conducted to screen the suitable trap crop among nine other plants (alyssum, wheat, phacelia, buckwheat, coriander, white clover, alfalfa, and kale) mainly by considering growth stages (vegetative and flowering), and select less susceptible kale cultivars among six other (Kestrel, Gruner, Sovereign, Regal, Corka and Colear). Alyssum (Lobularia maritima) and wheat (Triticum aestivum) were the most favoured potential trap plants for the wheat bug in a laboraotry study. Flowering stage of alyssum is the most susceptible growth stage by the bug damage. Kestrel and Coleor are the most popular kale cultivars used as forage brassicas in New Zealand, but they are the most susceptible to the wheat bug. Corka and Regal were the least susceptible cultivars. The integration of trap cropping technology by using alyssum as the trap crop, preferably depolying flowering stage, along with sowing less susceptible kale cultivars such as Corka and Regal in main fields have been suggested to protect brassica seedlings from bug damage.

Physiological Characteristics of Photosynthesis in Yellow-Green, Green and Dark-Green Chinese Kale (Brassica oleracea L. var. alboglabra Musil.) under Varying Light Intensities.

The objective of this work was to study physiological characteristics and photosynthetic apparatus in differentially pigmented leaves of three Chinese kale cultivars. Chlorophyll (Chl) fluorescence and photochemical reflectance index (PRI) measurements in green, yellow-green, and dark-green cultivars in response to varying light intensities. As light intensity increased from 200 to 2000 photosynthetic photon flux density (PPFD), fraction of light absorbed in photosystem (PS) II and PRI values in all plants were strongly lowered, but fraction of light absorbed in PSII dissipated via thermal energy dissipation and non-photochemical quenching (NPQ) values in all plants wereremarkably elevated.When plants were exposed to 200 PPFD, the values of fraction of light absorbed in PSII, utilized in photosynthetic electron transport(p), andfraction of light absorbed excitation energy in PSII dissipated via thermal energy dissipation (D), remained stable regardless of the changes in levels of Chla + b. Under 800 and 1200 PPFD, the values of p and electron transport rate (ETR) decreased, but D and NPQ increased as Chla + bcontent decreased, suggesting that decrease inChla + bcontent led to lower PSII efficiency and it became necessary to increase dissipate excess energy. On the contrary, in 2000 PPFD, leaves with lower Chla + bcontent had relatively higher p and electron transport rate (ETR) values and lower D level, as well as tended to increase more in NPQ but decrease more in PRI values. The consistent relations between PRI and NPQ suggest that NPQ is mainly consisted ofthe xanthophyll cycle-dependentenergy quenching.Yellow-green cultivar showed lower Chla + bcontent but high carotenoids/Chla + b ratio and had high light protection ability under high PPFD. The precise management of photosynthetic parameters in response to light intensity can maximize the growth and development of Chinese kale plants.

Organic Fertilizer Comparison on Growth and Nutrient Content of Three Kale Cultivars

Selecting supplemental nitrogen (N) fertilizer for use on certified organic farms can be difficult and confusing. There are many options commercially available to farmers with similar N concentrations but widely different ingredients. Experiments were conducted in a certified organic field and high tunnels near Fort Collins, CO in 2013 and 2014 to evaluate the impact of organic fertilizers on yield and nutrient concentrations of three kale (Brassica oleracea and Brassica napus) cultivars. This study includes an organic fertilizer (cyano-fertilizer), which is produced on-farm by growing N-fixing cyanobacteria (Anabaena cylindrica) in raceway ponds. The three fertilizer treatments were hydrolyzed fish emulsion, alfalfa (Medicago sativa) meal, and cyano-fertilizer. These were applied at rates calculated by subtracting soil nitrate concentration from a target 50 mg·kg−1 to the depth of 6 inches of soil. Cyano-fertilizer and hydrolyzed fish emulsion were applied in liquid form, while the alfalfa meal was incorporated dry into the soil before planting. Biweekly measurements of plant height were taken on three cultivars of kale: Dinosaur, Red Russian, and Winterbor. Leaf weight, leaf area, and N, iron (Fe), and zinc (Zn) concentrations were measured during three to four monthly harvests each year. Organized in a split-plot experimental design, there were three treatment replications with subplots of different kale cultivars. Fertilizer treatment did not significantly affect plant height, leaf weight, leaf area, or plant N, Fe, and Zn concentrations. However, there were cultivar differences in plant height, leaf area, and yield. Kale cultivar choice had a larger impact on yield and plant nutrient concentrations than fertilizer choice, because fertilizers were applied at similar N rates.

Influence of fertilisation on anthocyanin accumulation and acylation in Brassica oleracea

ABSTRACTA wide range of factors including biotic and abiotic stresses influence anthocyanin accumulation in plants. In this study, experiments were designed to measure the effects of nutrient depletion on anthocyanin accumulation in 3-week old juvenile Brassica oleracea seedlings of the red cabbage cultivar ‘Futurima’ and the red kale cultivar ‘Redbor’ that were grown in a hydroponic system. The effects of the depletion of single nutrients were compared to standard fertigation conditions. Plants were grown for 2 weeks in the absence of nitrogen accumulated higher anthocyanin levels than in all other treatments in both ‘Futurima’ and ‘Redbor’. Nutrient depletion treatments significantly influenced the percentage of anthocyanin diacylation in ‘Futurima’, but not in ‘Redbor’. A time-course experiment revealed that juvenile cabbage and kale seedlings accumulated maximal anthocyanin concentrations after 18 days without a supply of nitrogen. ’Redbor’ chromatograms were influenced by the localisation of anthocyanins in plant tissues, while nitrogen depletion treatments significantly increased anthocyanin concentrations in stems and leaves. In both greenhouse and growth chamber conditions, nitrogen depletion treatments in ‘Redbor’ significantly increased the percentage of diacylated anthocyanin compounds compared to control treatments in stems but not in leaves. These findings will help to optimise anthocyanin production in juvenile Brassica oleracea plants.

Changes in low molecular weight carbohydrates in kale during development and acclimation to cold temperatures determined by chromatographic techniques coupled to mass spectrometry.

Kale (Brassica oleracea) is a cool-season vegetable widely employed in the elaboration of diverse products such as tea and smoothies in USA or in the Northern German cuisine in wintertime. Besides, kale is gaining attention due to the diverse health benefits reported in the literature for its consumption, e.g. antigenotoxic and anticarcinogenic effect, protection of cardiovascular system and gastrointestinal tract. Low molecular weight carbohydrates (LMWC) are compounds directly related with kale flavour and nutritional quality. Despite different studies focusing on the chemical composition of kale, few information on LMWC is available. Thus, in this work a multianalytical approach was conducted in order to perform a comprehensive study of kale LMWC; their evolution during plant development and acclimation to cool temperatures was also evaluated. Gas chromatography coupled to mass spectrometry allowed the identification of 13 LMWC, being myo-inositol, galactinol, maltose and melibiose described for the first time in kale. Eight major LMWC were quantified in three different commercial kale cultivars using hydrophilic interaction liquid chromatography coupled to mass spectrometry to monitor possible differences in their content during plant development and as consequence of plant acclimation to cold temperatures. Overall, for all types of kales under study, the content of maltose and sucrose decreased during the plant development while the concentration of fructose, melibiose, maltose, raffinose and galactinol was increased in all kale types exposed to low temperatures. These results underline the importance of controlling the temperature during kale cultivation in order to obtain products with a high nutritional value.

Effect of cover crops on the yield and nutrient concentration of organic kale (Brassica oleracea L. var. acephala)

Kale is a leafy green vegetable regularly grown using non-organic agricultural systems. In recent years, organic kale demand has increased at near-doubling rates in the USA due to its perceived nutritional value. The objective of this study was to determine the effect of organic cover cropping systems on subsequent kale biomass production and nutrient composition (protein, mineral, and prebiotic carbohydrate concentrations) and to assess organic kale as a potential whole food source of daily essential mineral micronutrients and prebiotic carbohydrates. A single 100-g serving of fresh organic kale can provide mineral micronutrients (43–438 mg Ca; 11–60 mg Mg; 28–102 mg P; 0.5–3.3 mg Fe; 0.3–1.3 mg Mn; 1–136 µg Cu; and 0–35 µg Se) as well as 5.7–8.7 g of total prebiotic carbohydrates, including sugar alcohols (0.4–6.6 mg), simple sugars (6–1507 mg), raffinose and fructooligosaccharides (0.8–169 mg), hemicellulose (77–763 mg), lignin (0–90 mg), and unknown dietary fiber (5–6 g). Fresh organic kale has low to moderate concentrations of protein (1.3–6.0 g/100 g). Study results indicate that Starbor and Red Russian are the most suitable kale cultivars for organic production without considerable biomass and nutrient composition losses. Among the cover crops, faba bean results in the highest mineral, protein, and prebiotic carbohydrate concentrations in subsequent kale crops but ryegrass increases kale biomass production. Results also demonstrated a significant interaction between kale variety and organic cover crop with respect to biomass and nutrient concentration. Future organic nutritional breeding of kale is possible by selecting cultivars that perform well following different cover crops.

Cold stress modifies bioactive compounds of kale cultivars during fall–winter harvests

Kale is a plant known and valued since antiquity as a healthy vegetable crop, used for culinary, decorative, but also healing purposes. The aim of the study was to examine the effect of harvest date on physiological status and nutritional composition of two kale cultivars: ‘Winterbor’ F<sub>1</sub> (blue-green leaves) and ‘Redbor’ F<sub>1</sub> (red-purple leaves). The leaves were harvested in three periods: before frost (>0°C), after medium (−5.0°C) and heavy frost (−15.0°C). Content of dry weight, soluble sugars, l-ascorbic acid, carotenoids, chlorophylls, polyphenols, anthocyanins, as well as antioxidant activity and peroxidase activity were determined. Cold temperature significantly affected bioactive compounds of kale. The content of dry weight, soluble sugars, l-ascorbic acid, phenolics, and antioxidant activity increased after medium frosts for both cultivars. The level of anthocyanins also increased significantly for the ‘Redbor’ F<sub>1</sub> cultivar. After strong frost, most of the tested parameters (content of dry weight, soluble sugars, phenolics, anthocyanins, and total antioxidant and peroxidase activity) significantly increased. The chlorophyll <em>a</em> content was reduced by heavy frost in both seasons. Harvesting kale before and after frost may allow the level of biologically active ingredients to be regulated as cold also significantly affects the physiological status of the plants.

Identification and promotion of Korean cabbage and kale cultivars adapted to Uganda

Vegetables are important in nutrition and income security of rural and urban households. However, production and consumption in Uganda is below the WHO guidelines. This is attributed to pests/diseases, low soil fertility, little or no use of fertilizers, and low yielding cultivars, among others. The main objective of this study was to increase vegetable diversity and production in Uganda. Specific objectives were: i) identify high-yielding Korean vegetable cultivars adapted to Ugandan conditions; ii) develop low input (nutrient, pest/disease management) production options for sustainable production of the adapted cultivars. Five Korean cabbage (Brassica oleracea L.) and kale (Brassica oleracea L.) cultivars were evaluated under Ugandan conditions, against their local counterparts, over four seasons. The experimental design was completely randomised (CR), replicated three times. Korean cabbage cultivars ‘Jang-mi’, ‘Chu-no’ and Bul-am, and kale cultivars ‘Collard-menchu’ ‘Jeil-guijok’ and ‘Mat-jang’ produced higher marketable yield compared to local cultivars, hence more adapted. Cabbage production was most profitable with 100 kg NPK ha(-1), particularly on ‘Chu-no’, using cypermethyrine plus Dithane M45 for pests and disease control. For kale, production was highest with ‘Collard-menchu’. Eggyork mixture was most profitable on all three kale cultivars. From these results, the following production guidelines were developed for the Korean cultivars adapted to Uganda: Cabbage: ‘Chu-no’ using NPK (25:5:5) at 100 kg ha(-1), and cypermethyrine plus Dithane M45 for pests & disease control. For kale: ‘Collard-menchu’ using chicken manure at 4 t ha(-1) and cypermethyrine plus Dithane M45 for pests and disease control. There is need for further on-farm evaluation and eventual release of the adapted cultivars.

Differences in Leaf Color and Stage of Development at Harvest Influenced Phytochemical Content in Three Cultivars of Kale (Brassica oleracea L. and B. napus)

Microgreens and red colored plants have been suggested to contain higher level of health promoting phytochemicals. Kale (Brassica oleracea L. and other species) is regarded as a ‘superfood’ due to its antioxidant properties. In our study, three kale cultivars (B. oleracea L. ‘Dwarf Blue Curled’ and ‘Scarlet’, and B. napus ‘Red Russian’) differing in leaf pigmentation were harvested at five different leaf developmental stages and the concentrations of bioactive antioxidants compounds were evaluated. Carotenoids were measured by high performance liquid chromatography, and spectrometry analyses were used for total phenolics and anthocyanin measurements. Red leaf kale (‘Scarlet’) was generally higher in total carotenoids, phenolics, and anthocyanins than green leaf kales (‘Dwarf Blue Curled’ and ‘Red Russian’). As kale matured, water content decreased and dry mass increased. On a dry weight basis, total carotenoids were more abundant in microgreens and young seedlings with 4 to 6 true leaves (baby greens) than adult stage. In contrast, on a fresh weight basis, baby greens or adult kales generally contained more carotenoids and total phenolic compounds than microgreens, more likely due to the lower dry mass and phytochemical accumulation at microgreen stages. Although some microgreens vegetables may contain more health promoting phytochemicals, based on our study, higher phytochemicals were detected in young seedlings or mature leaves of kale.

Non-vernalization Flowering and Seed Set of Cabbage Induced by Grafting Onto Radish Rootstocks.

Cabbage (Brassica oleracea var. capitata) requires a long-term low-temperature exposure for floral induction, causing a delay in the breeding cycle. The objective of this study is to develop a method to induce flowering in cabbage without low-temperature treatment, using a grafting method. We conducted grafting experiments using two flower-induced Chinese kale cultivars (B. oleracea var. alboglabra) and seven radish cultivars/accessions as rootstocks and investigated the flowering response of grafted cabbage scions without low-temperature treatment. “Watanabe-seiko No.1” cabbage, when grafted onto the two Chinese kale cultivars, did not formed flower buds. Flowering was successfully induced in “Watanabe-seiko No.1” by grafting onto three out of the seven tested radish cultivars, and in “Kinkei No.201” and “Red cabbage” by grafting onto one tested radish cultivar. In “Watanabe-seiko No.1,” the earliest flower bud appearance was observed at 29 days after grafting. Seeds were also obtained from the three cabbage cultivars that flowered by grafting. Gene expression analysis of “Watanabe-seiko No.1” cabbage scions which formed flower buds by grafting, revealed high expression of the homolog of the floral integrator, SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (BoSOC1), at the time of flower bud appearance. However, in the same leaf samples, we observed low expression of two homologs of florigen, FLOWERING LOCUS T (BoFT.C2 and BoFT.C6). In addition, two homologs of the floral repressor FLOWERING LOCUS C (BoFLC3 and BoFLC4), which are known to be down-regulated before flower bud differentiation in the vernalization pathway, were highly expressed, indicating that grafting onto radish induces cabbage flowering independently of the vernalization pathway. The expression level of the radish FT homolog (RsFT) in “Rat’s tail-G2,” which had highly induced flowering in the grafted cabbage scion, was higher than in the other radish cultivars. However, although “Rat’s tail-CH” effectively induced flowering in the cabbage scion, the expression of RsFT was low in this cultivar. In this study, floral induction of non-vernalized cabbage cannot be explained by the expression levels of RsFT in rootstock plants, alone. The flowering of non-vernalized cabbage would be induced by transmissible agents from rootstocks and not by the expression of cabbage FT, BoFT, from the scion itself.

Susceptibility of kale cultivars to the wheat bug, Nysius huttoni (Hemiptera: Lygaeidae) in New Zealand

ABSTRACT Seedlings of kale cultivars in New Zealand are highly susceptible to direct feeding by the wheat bug Nysius huttoni (Hemiptera: Lygaeidae), an endemic insect pest. Two assays (choice and no-choice) were conducted to compare the relative susceptibility of seedlings of the six most popular kale cultivars in New Zealand (Kestrel, Gruner, Sovereign, Regal, Corka and Coleor). The earliest occurrence of feeding damage in the choice assay was on cv. Kestrel, significantly earlier than on Corka and Gruner. In the no-choice assay, significantly more wheat bugs were found on Kestrel than on Corka. Damage to Kestrel occurred significantly earlier than on all the other cultivars except Corka. Reduction in plant dry weight was significantly higher on Coleor and Kestrel. These results are important for developing integrated pest management protocols for kale pests.

Biology and Management of the New Zealand Endemic Wheat Bug, Nysius huttoni (Hemiptera: Lygaeidae)

Abstract The wheat bug, Nysius huttoni White, mainly reported as a pest of wheat and forage brassicas, is native to New Zealand. This pest has been accidentally introduced into The Netherland and Belgium during apple exports from New Zealand. The bug population is abundant in open sparse vegetations and hot-dry habitats, and feeds on dropping seeds. It damages wheat grains during milk-ripe stage by piercing through the glumes into the developing grains that can reduce gluten protein and reduce baking quality. Bugs also suck phloem fluid from seedlings, which can reduce plant establishment in forage brassicas. Early scouting and field monitoring are suggested before making pest management decisions. Seed treatment with neonicotinoids, permethrin, and chlorpyrifos spray in the standing crops are chemical methods of management in New Zealand. These conventional synthetic pesticides have nontarget effects on human health, the environment, and biodiversity. However, preventive measures such as the use of less-susceptible cultivars, and using potential trap crops is other important pest management options. Alyssum (Lobularia maritima L. Desv. Brassicales: Brassicaceae) and wheat (Triticum aestivum L. Poales: Poaceae) are two potential trap crops of wheat bug. Kale (Brassica oleracea L.) cultivars, such as Corka and Regal, and wheat (Triticum aestivum) cultivars, such as Batten, Domino, and Oroua, are less-susceptible cultivars. Understanding the biology and ecology of the pest, and utilizing preventative pest management measures such as the use of trap crops and less-susceptible cultivars, and integrating these with ‘soft’ chemicals make a suitable integrated pest management strategy for this pest.

Susceptibility of kale cultivars to the wheat bug, Nysius huttoni (Hemiptera: Lygaeidae) in New Zealand

Seedlings of kale cultivars are highly susceptible to direct feeding by the wheat bug Nysius huttoni (Hemiptera: Lygaeidae), an endemic New Zealand insect pest. Damage from this pest leads to reduced plant establishment so is currently managed by prophylactic use of pesticides. Encouraging farmers to use less susceptible kale cultivars can reduce pesticide costs and improve the environment. A series of choice and no-choice tests was conducted in a controlled-temperature room to evaluate the relative susceptibility of seedlings of the six most widely grown kale cultivars in New Zealand (Gruner, Kestrel, Regal, Colear, Corka, and Sovereign). Bugs settled most readily on Kestrel in both sets of tests, although mean settlement times did not differ significantly among cultivars. However, feeding damage on Kestrel occurred significantly earlier than on Corka or Gruner. These results indicate that Kestrel is the cultivar most susceptible to wheat bugs and that pesticide use could be reduced if less susceptible cultivars were more widely grown in New Zealand. These results also provide important information for developing integrated-management protocols for brassica pests.

The effect of kale cultivar and sowing date on dry‐matter intake, crop utilization, liveweight gain and body condition score gain of pregnant, nonlactating dry dairy cows in winter in New Zealand

AbstractAn outdoor grazing study on kale was conducted with pregnant, nonlactating (dry) dairy cows over a 42‐day winter grazing period commencing 9 June 2008. Kale treatments consisted of two kale cultivars varying in leaf:stem proportion (“Regal,” a leafy variety and “Caledonian,” a stemmy variety) and two sowing dates (8 November and 15 December). Measurements were made for dry‐matter (DM) utilization, apparent DM intake, liveweight gain and changes in body condition score (BCS) for a total of 120 cows allocated to three replicate groups of the four factorial treatments. Cows were offered a daily allowance of 10 kg DM/cow of kale and 2.2 kg DM/cow of straw. Pregrazing DM yield was higher for kale sown in November (16,517 kg DM/ha) than December (13,867 kg DM/ha), but was unaffected by cultivar (average 15,192 kg DM/ha). “Regal” kale had a higher percentage of leaf compared with “Caledonian” (33.6% vs. 25.6%), lower content of NDF (32.4% vs. 34.1%), but similar metabolizable energy content (12.1 MJ/kg DM for both) in the whole plant. Despite the differences in pregrazing DM yield and forage quality among treatments, no differences were found in DM utilization (between 88.5% and 90.2%), apparent DM intake (between 9.4 and 9.6 kg DM/cow.day), liveweight gain (between 0.53 and 0.67 kg/cow.day) and BCS gain (between 0.43 and 0.46 unit/cow over 42 days). Manipulation of kale yield and quality through choice of cultivar and sowing date had no effect on the performance of pregnant, nonlactating dairy cows.