Effects of clipping frequency on tiller development of crested wheatgrass and hybrid bromegrass at vegetative and reproductive stages

Information on the tiller development of hybrid bromegrass (Bromus inermis × Bromus riparius Rehm) is limited. The objective of this study was to evaluate the effect of clipping frequency at the vegetative and reproductive stages on the tiller development and concentrations of sugars of ‘AC Knowles’ hybrid bromegrass compared to ‘Kirk’ crested wheatgrass (Agropyron cristatum L.). This experiment was conducted in the greenhouse using the tillers of the vernalized plants dug from the field. The experimental design was a randomized complete block design. Grasses were clipped once or four times at either vegetative or reproductive stage. Regardless of the growth stage, four clippings reduced the tiller number of hybrid bromegrass by 25.9% compared to the undefoliated control while single clipping had no impact. The four clipping had no impact on the tiller number of crested wheatgrass, while single clipping increased its tiller number on average by 50.4% at both growth stages. Crested wheatgrass produced 16.6% more tillers than hybrid bromegrass under the single clipping. The two grass species had a similar number of axillary buds under different clipping treatments. The axillary bud size of crested wheatgrass was larger than hybrid bromegrass. All axillary buds were viable under the two clipping treatments for both grasses. Four clippings significantly decreased the stem base glucose concentration of the two grasses and the root sucrose concentration of crested wheatgrass. Hybrid bromegrass was less tolerant to frequent clippings than crested wheatgrass. Therefore, intensive grazing of hybrid bromegrass pasture may result in a thin stand.

Horn bud size of dairy-bred and suckler-bred calves at time of disbudding

Background Hot-iron disbudding is a common management procedure to prevent horn growth in calves. The study objective was to examine effect of age, breed and sex on horn bud size of dairy-bred and suckler-bred calves at time of disbudding. Results The left and right horn bud size (diameter and height in mm) of 279 calves, including dairy-bred Holstein-Friesian (Male (M) = 88) and 191 suckler-bred (86 Charolais, CH; (M = 39, Female (F) = 47), 67 Limousin, LM; (M = 32, F = 35) and 38 Simmental, SI; (M = 22, F = 16) sired)) was measured using a digital calliper at time of disbudding. Calves were retrospectively assigned to two age categories at time of disbudding: 1), 14 to 28 days (d) old and 2), 29 to 60 d old. Holstein-Friesian M calves had a greater horn bud diameter (16.97 v.14.45 mm) and height (7.79 v. 5.00 mm) compared to suckler-bred M calves (P < 0.01), with no difference (P > 0.05) among the suckler-bred calves. Suckler-bred M calves had a greater horn bud diameter (14.46 vs 13.29 mm) and height (5.01 vs 3.88 mm) compared to suckler-bred F calves (P < 0.05). The slopes of the lines of best fit show that horn bud diameter and height increased with age (P < 0.05) for HF, SI male and CH female calves while there was no relationship with age (P > 0.05) for CH and LM male calves, or for SI and LM female calves. Linear regression of age with diameter and with height for each breed and sex showed high variability in the data as indicated by R-squared values ranging from 0.003–0.41 indicating that in the case of the diameter and the height, the weight of the fitting effect was poor. Conclusions Calf age is not a good predictor of horn bud size and recommendations for the disbudding of calves should be based on horn bud size and not on age. The implications of these findings are that calves should be disbudded while horn development is still at the bud stage and when the bud is large enough to be easily palpable/visible, but not so large that disbudding could lead to severe tissue trauma.

Direct embryogenesis from anther culture of hot chilli Capsicum annuum L.

In Viet Nam, local varieties of chili have a distinctive aroma and pungency. However, the generation of pure lines from pollen culture in local hot chilli has been very limited reported. Therefore, this study was to relate flower bud size with microspore developmental stages and the culture media have concentration changed of growth regulator effects on the in vitro androgenesis. Flower buds were randomly collected and visually divided into three stage based on both petal and sepal size. Then anther was cultured on MS basal medium with different concentration of hormones NAA changed 0.1 - 0.7 mg/L and kinetin changed 1.0 - 3.0 mg/L, BA changed 0.5 - 1.5 mg/L. The results showed that bud flower have anthers are light violet in color, 2.5 mm long, consisted of anthers with 80 % uni-nucleate and 20 % bi-nucleate microspores were selected. In induction culture media, it was observed that MS medium with 2.0 mg/L Kinetin and 0.5 mg/L NAA gave higher embryo frequency. MS medium with 1 mg/L BA is the best medium for embryo germination and inducting shoots. And ½ MS medium for shoot elongation and rooting.

Developmental timing scales wing patterning between avian species

How development is timed between differently sized species is a fundamental question in biology. To address this problem, we compared wing development in the quail and the larger chick. We reveal that developmental timing is faster in the quail than in the chick, and is associated with pattern specification, proliferation, organiser duration, differentiation and apoptosis. However, developmental timing is independent of the growth rate, which is equivalent between both species, and therefore scales pattern to the size of the wing. We reveal that developmental timing can be either maintained or reset in interspecies tissue grafts, and we implicate retinoic acid as the resetting signal. Accordingly, retinoic acid can switch species developmental timing and rescale pattern, both between the quail and chick, and the chick and the larger turkey. We suggest that the scaling of pattern to wing bud size is achieved by the modulation of developmental timing against a comparable rate of growth.Summary- We show that developmental timing scales wing patterning

Effect of Chemical Composition of Nutritive Medium and Explant Size Over Androgenetic Response in Microspore Culture of Brassica oleracea L.

The dimension of the bud is a key factor for the orientation of microspore culture and the success of obtaining double haploid plants as it is a strong correlation between bud size and the developmental stages of microspores, and it is specific for each plant species and genotype. Our study was focused to determine the correlation between morphological characteristics, namely floral bud size and specific microspore developmental stages in order to determine the proper size, suitable for a successful protocol of obtaining double haploid plants in Brassica oleracea var. italica. Thus, we tested four bud sizes ranging from 2.0 to 4.0 mm measured from the base to the tip of the bud. After the statistical analysis of the results it can be emphasized that the best results were obtained in the case of using as a source of microspores the flower buds with the size between 3.1-3.5 mm. At this dimension, the share of microspores in the uninucleate stage, predominantly in the late uninucleate stage, is 90%, thus ensuring a homogeneous population of microspores in the optimum stage of development. Their evolution is predominantly embryogenic, the percentage of microspores following the gametophytic pathway is reduced, by only 9.12%.

Molecular genetic characteristics of broccoli (Brassica oleracea L. var. italica Plenck) from the VIR collection

Background. Broccoli is an early-ripening vegetable crop that contains many biologically active compounds and mineral elements. According to the Genesys database, the global genebank collections contain no more than 465 different broccoli accessions. Fourteen cultivars and hybrids developed in Russia are registered in the State Register of the Russian Federation. The need to improve the assortment in a number of important breeding target areas (small habitus, non-spawning, bud size, disease resistance, etc.) requires the use of new effective techniques, including marker-assisted selection methods and association mapping. In this regard, it seems relevant to evaluate the VIR collection of broccoli using molecular genetic markers, which will provide new source material for breeding.Materials and methods. A molecular genetic study involved 39 broccoli cultivars and hybrid populations of different geographical origin, with various biological characteristics, and for various uses. For the analysis, 35 markers of microsatellite sequences specific to the Brassica L. genome were selected. PCR products were separated by electrophoresis on a 3% agarose gel.Results and conclusions. As a result, 110 polymorphic fragments were identified. In the studied loci, 3 to 7 alleles were pinpointed. The discriminating power of markers ranged from 0.75 to 0.96, and averaged 0.91; the average number of fragments per marker was 4.4. Ten unique alleles and 12 rare alleles (found in less than 8% of the samples) were observed in the studied accessions. On the other hand, the 201 bp allele of the locus BC65 was found in 95% of accessions, that is, it was almost common. All used markers have a sufficiently high diagnostic value and can be recommended for DNA identification in broccoli cultivars. An analysis of the genetic similarity of the collection accessions, carried out in the DarWin program using the Unweighted Neighbor-Joining method, made it possible to establish four closely related clusters.

Pollen Viability and Microspore Culture in Three Broccoli Cultivars (Brassica oleracea L. var. italica Plenck)

Broccoli is a high value vegetable crop in Indonesia, however production is low due to limited number of suitable cultivars, so, breeding hybrid broccoli for warm climate is important. The first step in hybridization is providing homozygote parent plants which can be done efficiently via microspore culture. The objectives of this study were to determine 1) bud size that produce uninucleate microspore stage appropriate for culture; 2) pollen viability, 3) microspore development, in three broccoli cultivars (‘BL 10001’, ‘Royal Green’ and ‘Green Magic’). Various bud size (1 – 5 cm) was squashed and observed microscopically to determine bud size containing uninucleate microspore. Pollen viability was determined by IKI staining and pollen germination method. Chromosome number was counted on root tips using squash method with aceto-orcein stain. Various heat treatment schemes were conducted to induce microspreo development. Result showed uninucleate microspore derived from 2-3 mm and 3-4 mm bud length of ‘BL-10001’ and ‘Royal Green’ was responsive for microspore development in culture. Pollen viability varied among cultivars, 78-87% on IKI method and 15-16% on germination test. Microspore culture showed different embryogenesis response; pollen-like structure was produced by ‘BL 10001’.

Anatomical Structure of Sepal and Petal of Red Dragon Fruit (Hylocereus polyrhizus Britton & Rose) During Flower Development

Red dragon fruit (Hylocereus polyrhizus Britton & Rose) is one type of cactus plant which is very potential as an ornamental plant and edible fruit. Flower is organ that play an important role in the process of breeding plants generatively. This reasearch aimed to study the anatomical structure of sepals and petals of red dragon fruit plants during flower development. The research stages included: sepals and petals sampling that held at various stages of flowering ; morphological observation (measurement length of sepals and petals); anatomical slides of sepals and petals cross section using the embedding method, anatomical observation and image capture of sepals and petals. The parameters observed were bud size, sepal length, petal length, sepal thickness, petal thickness, and tissue description composed. The results of this study indicated that buds have an increased development pattern. The increase in bud size is directly proportional to the stage of the bud. Sepal and petal are composed of epidermal tissue which form papillae, cryptophore stomata, secretory parenchyma space containing mucus, and tissues transport system is closed collateral.

Floral Meristem Development in Cranberry Apical Buds during Winter Rest and Its Implication on Yield Prediction

The formation and development of floral meristems is key to fruit production. However, limited information regarding the development of floral buds during the dormant period of cranberry (Vaccinium macrocarpon) constrains the ability to forecast yield early and accurately. The objectives of this study were to characterize the development of floral meristems from fall to spring and to evaluate the number of floral meristems formed across different bud sizes and upright types, as well as their contribution to the fruit production of the next year. Apical buds of different sizes on vegetative and fruiting uprights were tagged and collected periodically from fall to spring for histological study. An extra set of tagged buds was left in the field to evaluate their flower and fruit production. Five stages of floral development were identified based on the concentric differentiation of organ primordia. Large buds from vegetative uprights developed earlier, had a higher number of floral meristems, and became fruiting uprights; they had the highest number of flowers and fruit. Buds from fruiting uprights had the lowest number of floral meristems and delayed development; subsequently, they had the lowest number of fruit per upright. Our results provide evidence of active floral meristem differentiation during fall and winter, as well as differences in the timing and development stage according to bud size. In addition, our study shows that upright types and bud sizes influence the fruit production of the following year; therefore, they should be considered in cranberry crop forecasting models.