Utilization of a Sugarcane100K Single Nucleotide Polymorphisms Microarray-Derived High-Density Genetic Map in Quantitative Trait Loci Mapping and Function Role Prediction of Genes Related to Chlorophyll Content in Sugarcane

Chlorophyll is the most important pigment for plant photosynthesis that plays an important role in crop growth and production. In this study, the chlorophyll content trait was explored to improve sugarcane yield. Two hundred and eighty-five F1 progenies from the cross YT93-159 × ROC22 with significantly different chlorophyll contents were included as test materials. The chlorophyll content of the +1 leaves during elongation phase was measured using a SPAD-502 meter through a three-crop cycle (plant cane, first ratoon, and second ratoon). Linkage analysis was conducted on a high-density genetic map constructed based on the sugarcane 100K SNP chip. In addition, Fv/Fm, plant height, stalk diameter, brix data were collected on plant cane during the elongation and maturation phases. The results showed that the +1 leaf SPAD values, which can be used as an important reference to evaluate the growth potential of sugarcane, were significantly and positively correlated with the Fv/Fm during elongation phase, as well as with plant height, stalk diameter, and brix during maturity phase (P < 0.01). The broad sense heritability (H2) of the chlorophyll content trait was 0.66 for plant cane crop, 0.67 for first ratoon crop, and 0.73 for second ratoon crop, respectively, indicating that this trait was mainly controlled by genetic factors. Thirty-one quantitative trait loci (QTL) were detected by QTL mapping. Among them, a major QTL, qCC-R1, could account for 12.95% of phenotypic variation explained (PVE), and the other 30 minor QTLs explained 2.37–7.99% PVE. Twenty candidate genes related to chlorophyll content were identified in the QTLs plus a 200-Kb extension region within either sides, of which four were homologous genes involved in the chlorophyll synthesis process and the remaining 16 played a certain role in chlorophyll catabolic pathway, chloroplast organization, or photosynthesis. These results provide a theoretical reference for analyzing the genetic mechanism of chlorophyll synthesis and subsequent improvement of photosynthetic characteristics in sugarcane.

Multi-layer Budding of Oversized Rubber (Hevea brasiliences) Seedlings: Success and Growth in Different Soil Media

The study on Multi-layer budding of oversized rubber seedling aimed at evaluating the success of multiple budding operation on single seedling of rubber tree species comprising of 4 to 7 budding layers per seedling. The experiment used randomized complete blocked design layout with 3 treatments such as 4, 5 and 7 layer budding in a single seedling replicated 4 times. Results revealed that the highest number of budding layers succeeded significantly higher as compared to 4 and 5 layers. The main survival percentage is about 79.17% for the 7 layers, 76.52% for the 5 layers and only about 55.36% for the 4 layers. Pure garden soil reported to have significant results on sprouting rate, sprout length, stalk diameter and number of leaves. This finding emphasized that budding of rejected oversized rubber seedlings grown in an abandoned nurseries can be reutilized for mass production of budded cuttings through multiple budding of 7 layers per seedlings to maximize planting materials derived from single seedlings.

Effect of plot size and plant spatial arrangement on the efficiency of family selection in sugarcane

The purpose of this study was to identify the ideal sample size representing a family in its potential, to identify superior families and, in parallel, determine in which spatial arrangement they may have a better accuracy in the selection of new varieties of sugarcane. For such purpose, five families of full-sibs were evaluated, each with 360 individuals, in the randomized blocks design, with three replications in three different spacing among plants in the row (50 cm, 75 cm, and 100 cm) and 150 cm between the rows. To determine the ideal sample size, as well as the better spacing for evaluation, the bootstrap method was adopted. It was observed that 100 cm spacings provided the best average for the stalk numbers, stalk diameter and for estimated weight of stalks in the stool. The spacing of 75 cm between the plants allowed a better power of discrimination among the families for all characters evaluated. At this 75 cm spacing was also possible to identify superior families with a sample of 30 plants each plot and 3 reps in the trial. Highlights The bootstrap method was efficient to determine the ideal sample size, as well as the best spacing for evaluation. The 75-cm spacing had the highest power of discrimination among families, indicating that this spacing is the most efficient in evaluating sugarcane families for selection purposes. From all the results and considering selective accuracy as the guiding parameter for decision making, the highest values obtained considering the number of stalks and weight of stalks in the stools were found at the 75-cm spacing.

Meta-analysis of QTLs associated with popping traits in maize (Zea mays L.)

The rising demand for popcorn necessitates improving the popping quality with higher yield of popcorn cultivars. Towards this direction several Quantitative Traits Loci (QTLs) for popping traits have been identified. However, identification of accurate and consistent QTLs across different genetic backgrounds and environments is necessary to effectively utilize the identified QTLs in marker-assisted breeding. In the current study, 99 QTLs related to popping traits reported in 8 different studies were assembled and projected on the reference map "Genetic 2005" using BioMercator v4.2 to identify metaQTLs with consistent QTLs. Total ten metaQTLs were identified on chromosome 1 (7 metaQTLs) and 6 (3 metaQTLs) with physical distance ranging between 0.43 and 12.75 Mb, respectively. Four identified metaQTLs, viz., mQTL1_1, mQTL1_5, mQTL1_7 and mQTL6_2 harboured 5–8 QTL clusters with moderately high R2 value. The clustered QTLs were from two or more experiments. Based on the expression pattern in endosperm and pericarp tissues, a total of 229 genes were selected. Nineteen of these genes are involved in carbohydrate metabolism. Of the 19 genes specifically involved in carbohydrate metabolism, 11 of them were in these regions, implying the importance of these clustered QTLs. MetaQTL1_1 at bin location 1.01 coincided with the reported QTLs related to various agronomic traits like stalk diameter, tassel length, leaf area and plant height. The identified metaQTLs can be further explored for fine mapping and candidate gene identification, which can be validated by loss or gain of function. Identified metaQTLs can be used for introgression of popping traits towards enhancing the popping ability.

Performance of gerbera varieties under naturally ventilated polyhouse

An experiment was conducted to evaluate ten varieties of gerbera under polyhouse conditions in Hyderabad. Vegetative, flowering and flower characters varied significantly among the cultivars and variations in different growth parameters were prominent. Mean performance of the cultivars revealed that cv. Helix recorded maximum plant height, flower diameter, flower stalk diameter and ray florets. The same cultivar Helix also produced maximum number of suckers per plant, number of flowers per plant, Fresh weight of flower, dry weight of flower and possessed longest field life which was at par with cv. Goliath. The cv. Goliath found superior with respect to maximum chlorophyll content, minimum days required for commence of first-flower and days taken for 50% flowering.Maximum disc diameter and number of leaves were produced by cv. balance. While cv. Savannah had significantly maximum leaf area and length of the flower stalk. However, the cv. ‘Montenegro recorded least mean value in terms of plant height, number of leaves per plant, leaf length, leaf breadth, leaf area, number of suckers, chlorophyll content, flower diameter, flower stalk diameter, ray florets, disc diameter, number of flowers per plant and took maximum days for first flower opening, 50 % flowering and which was late in inducing flowering had lesser duration of flowering. Cultivar Helix exerted best performance on various growth and flower characters along with the cultivars Goliath, Danaellen, Balance and Savannah.

Blood meal as nitrogen source and its effect on disease severity on sweet corn

A blood meal is a by-product of the meat processing industry and can be used as nitrogen fertilizer due to its minimum content of 10 % Nitrogen. The objective of this work was to evaluate the effect of doses of blood meal, such as nitrogen fertilizer in topdressing, on the production components and the severity of diseases in sweet corn. The experiment was developed at the Federal Institute of Education, Science and Technology of Mato Grosso do Sul (IFMS), Ponta Porã campus, in a Quartzarenic Neosol. The experimental design used was randomized blocks with five treatments of blood meal doses of (0 kg ha-1; 48 kg ha-1; 96 kg ha-1; 120 kg ha-1 and 144 kg ha-1) and one treatment using urea for topdressing fertilization with 120 kg ha -1 of N. The experiment analyzed the severity of white spot on the tasseling and milk grain stages and also the production components: plant height, insertion height of the first ear, stalk diameter, length of the unhusked commercial ears, diameter of unhusked commercial ears, number of grain row, weight of husked commercial ears, weight of unhusked commercial ears and productivity in kg ha-1. The use of blood meal was as efficient as the use of urea as a nitrogen fertilizer for doses starting from 48 kg ha-1, the maximum productivity was obtained when the dose of 112 kg ha-1 of N blood meal was used. The severity of the white spot did not progress in treatments containing nitrogen fertilization in topdressing.

Halyomorpha halys (Hemiptera: Pentatomidae) as a Potential Risk for Early Vegetative-Stage Sweet Corn

Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) is an invasive species in the United States representing a great threat to crops of economic importance, such as soybean and corn. Due to the lack of information about its damage to early vegetative-stage corn, this study was conducted to provide information about H. halys damage to sweet corn seedlings. In the field experiment, caged sweet corn seedlings were exposed to sexed H. halys adults of densities of 0, 1, or 2 insects per plant for 7 d. In a complementary greenhouse experiment, caged sweet corn seedlings were exposed to 0 or 2 nonsexed H. halys at different stages (second to fifth instars and adult) per plant for 14 d. In both experiments, we evaluated plant fresh and dry weights, plant height, stalk diameter and plant injury (using a rating scale, 0 to 5). In the field experiment, plant injury based on the rating scale was greater in plants exposed to insects compared with the control. In the greenhouse experiment, fresh and dry weights, height and diameter of seedlings were lower for those exposed to fourth instars. This stage also caused greater injury based on the rating scale. In general, our results indicate that H. halys can feed on sweet corn seedlings, and that fourth instars cause more injury. The rating scale adapted here can be used for early identification of H. halys occurrence and to assess its injury in the field.

Physiological response of maize under different fertilization management under drought condition

This work was aimed to evaluate the development of maize cultivated under different fertilization management, in order to establish an alternative for mineral fertilization. The experiment was carried out in the experimental area of Chã de Jardim, in Areia, Paraíba, Brazil. Six treatments were used with four replications. Plant height, stalk diameter, leaf number, chlorophyll a, b and total, photosynthetic rate, transpiration, stomatal conductance and internal CO2 concentration in the leaf were evaluated. In the 30 days after emergence, superiority of treatments was observed in the plants under chemical fertilization for plant height and number of leaves. For diameter of stalk the treatment organic fertilization + P and K showed superiority. At 60 days after planting the chemical fertilization provided the highest averages for plant height and stalk diameter. For the photosynthetic rate, transpiration and internal CO2 concentration, the treatment that presented the highest average was observed in plants under organic fertilization combined with P and K and N added in top-dressing. For the chlorophyll, the chemical fertilization provided the highest values. Organic fertilization in association with mineral fertilizers provided results close to those observed in mineral fertilization, being an alternative for nutritional management in maize.

Effect of Bacillus aryabhattai on the initial establishment of pre-sprouted seedlings of sugarcane varieties

This study proposes to examine the potential use of Bacillus aryabhattai in pre-sprouted seedlings of sugarcane inoculated with the microorganism when subjected to different regimes of water supply after transplanting. The experiment was laid out in a randomized-block design with a complete 3 × 2 × 5 factorial arrangement, in five replicates. The factors were represented by pre-sprouted seedlings of three sugarcane varieties (IAC 911099, RB 855156 and CTC 20), two seedling types (inoculated and not inoculated with B. aryabhattai) and five frequencies of water supply, which provided the ability of return to 100% soil field capacity, at every 0, 10, 20, 30 and 40 days. Plant mortality, plant height, number of leaves, stalk diameter and number of tillers were evaluated throughout the experimental period. At the end of the study, the shoot dry matter (SDM) and root dry matter (RDM) contents of the plants were measured. The number of leaves on the plant was affected only in isolation, according to the cultivar, without effects of the other studied factors. There was a double interaction effect between the factors of variety and inoculation (V*I) for the variables of SDM, stalk diameter and height; and between frequency and inoculation (F*I) for stalk diameter. There was a triple interaction effect between variety, inoculation and frequency (V*I*F) for the RDM variable. Thus, the use of B. aryabhattai as an inoculant in pre-sprouted seedlings of sugarcane at the time of seedling formation can improve plant development after transplanting depending on the cultivar used, especially in IAC 911099 and RB 855156.

Impact of Integrated Nutrient Management (INM) for Sustainable Production of Sprouting Broccoli (Brassica oleracea L. var. italica Planck)

The investigation was conducted at Vegetable Research Station, Kalyanpur, C. S. A. University of Agriculture and Technology, Kanpur, Uttar Pradesh during 2018-19 and 2019-20 to find out the effect of different levels of inorganic and organic fertilizers with the combination of biofertilizers on the sustainable production of sprouting broccoli. The experiment was laid out in a Randomized Block Design (RBD) with three replications. Results revealed that application of Vermicompost @ 5 t ha-1 + Azotobacter gave a significant effect on yield and yield attributing characters viz., days to first curd initiation, days to 50% curd initiation, stalk diameter, stalk length, curd diameter, curd length, curd width, days to curd maturity, weight of curd with guard leaves, weight of curd without guard leaves, weight of curd after 24 hours at room storage and curd yield as compared to other treatments.