Proceedings, Volume 36; doi:10.3390/proceedings2019036195
In rapeseed and mustard, the major diseases (downy mildew, white rust, Alternaria blight and Sclerotinia stem rot) cause 37–47%loss in pod formation and 17–54% reduction in grain yield. The identification of new sources of resistance is a high priority in breeding programs. About 3000 germplasm accessions of Indian mustard were evaluated under multiple environments (3 seasons) at hot spots (4 locations) and under artificial epiphytophic conditions against insect pests and diseases (aphids, white rust, powdery mildew and Alternaria blight). Accessions IC265495, IC313380, EC766091, EC766133, EC766134, EC766192, EC766230, EC766272 were identified as highly resistant to white rust (A. candida) with disease severity reaction (Percent disease severity Index, PDI = 0) under artificial inoculation. Accession RDV 29 showed the inheritance of resistant source for powdery mildew in Indian mustard. Screening of brassica wild relatives (about 25 species) for white rust found that Brassica fruticulosa, Brassica tournefortii, Camelina sativa, Diplotaxis assurgens, D. catholica, D. cretacia, D. Erucoides, D. Muralis, Lepidium sativum had highly resistance (PDI = 0) to Delhi isolates of white rust. Several traits identified from cultivated and related species will be useful for genetic improvement of rapeseed and mustard.
Proceedings, Volume 36; doi:10.3390/proceedings2019036193
Heterosis, or hybrid vigour, is the superiority of the hybrid for a certain trait over the mean of its two parents. Heterobeltiosis is a form of heterosis where the hybrid is superior to its best parent. Banana breeding is a tedious, time-consuming process, taking up to two decades to develop a hybrid. Understanding heterosis in banana breeding will contribute to selecting right breeding materials for further crossing, thus increasing banana breeding efficiency. Here we document heterobeltiosis by using the recently bred NARITA ‘Matooke’ hybrids and their ancestors. NARITA hybrids, their parents (4x and 2x), grandparents (3x and 2x), and local 3x ‘Matooke’ cultivar checks were planted in a rectangular lattice design with two replications. Yield and other agronomic data were collected at flowering and harvest. The NARITAs were compared with their 3x ‘Matooke’ grandmothers. Heterobeltiosis on bunch weight was calculated with the data of 3 cycles. All the NARITAs showed heterobeltiosis for bunch weight. NARITA 17 had the highest grandparent heterobeltiosis (ca. 250%). Genetic gains due to crossbreeding were determined for fruit yield considering three generations: matooke cultigen (C0), primary tetraploid hybrids (C1) and secondary tetraploid hybrids (C2). The average genetic gain (from C0 to C2) rates for bunch weight (kg) and yield potential (t ha−1 year−1) were 1.4% and 1.3% per year, respectively.
Proceedings, Volume 36; doi:10.3390/proceedings2019036196
Terminal drought stress is currently a major constraint in many wheat production regions. This is predicted to worsen with future climate change. The stay-green phenotype allows crops to remain green and photosynthesize for longer after anthesis, potentially improving yields in terminal drought environments. Root systems with greater root length density at depth can contribute by increasing access to deep soil moisture late in the season. To study the genetics of root and stay-green traits in wheat, a multi reference parent nested association mapping (NAM) population was developed. Using the “speed breeding” system of rapid generation advance, over 1500 recombinant inbred lines (RIL) were generated in approximately 18 months. Genome-wide association studies (GWAS) using a novel whole-genome NAM method (WG-NAM) identified genetic regions associated with the target traits. High-throughput techniques were developed and used for the NAM lines to (i) phenotype seedling roots in controlled conditions, and (ii) objectively characterize novel stay-green traits for hundreds of genotypes in standard yield plots in the field. NAM lines were phenotyped for yield and stay-green traits at multiple water-stressed and non-stressed environments during 4 seasons. Particular traits were associated with superior adaptation to certain environments. Many lines with adaptive root and stay-green traits exhibited superior yield to the reference parent in relevant target environments and 54 such lines have been provided to commercial Australian wheat breeders for cultivar development. This combination of technologies is increasing understanding of physiological adaptation to water-limited environments in wheat and helping accelerate genetic progress.
Proceedings, Volume 36; doi:10.3390/proceedings2019036197
Glucosinolates (GSLs) are secondary metabolites produced by members of the genus Brassica. These compounds impart the pungency to brassica vegetables and oils. Due to their health benefits, which include anti-cancer and anti-fungal properties, they have been attracting interest in research. Indian mustard (B. juncea L.), used as condiment and oil crop has high natural levels of seed glucosinolates and displays exploitable natural variation in this trait. In this study a diverse collection of 161 mustard lines originating from 21 countries, will be genotyped and phenotyped. Traits of interest include seed GSLs (sinigrin, gluconapin, progroitin, epi-progoitin and glucoiberin), oil and protein content, as well as basic agro-morphological performance such as height, flowering time and yield. Current knowledge on GSL biosynthesis and its genetic regulation mostly relies on data from Arabidopsis thaliana. We aim to elucidate the genetic architecture of GSL content and composition in relation to other seed traits (oil and protein content) in our diversity panel through association mapping. Additionally, we are aiming to resolve genome complexity of GSL genes in mustard genome in contrast to A. thaliana by identifying gene copy number through in silico analysis. Outcome of this study will help streamline the breeding and product development for either high GSL mustard lines for condiment use or low GSL lines for canola-type oil use. Our preliminary data on seed GSLs seems to reflect the historical use of mustard in different geographical regions. Chinese and European lines featured higher GSL while lines from the Indian subcontinent displayed lower GSL contents.
Proceedings, Volume 36; doi:10.3390/proceedings2019036198
The effects of increasing CM level in corn-animal protein-based diets and enzyme supplementation in broilers was investigated in a 30-day experiment. A total of 168, one-week old Cobb broilers were assigned to 8 diets consisting of 2 controls (with and without enzyme) and 6 other diets with 15, 30 and 45% CM levels with and without enzyme in a completely randomized design. Results showed significant interactions effects on growth parameters, fat digestibility, White Blood Cell (WBC) count, Saturated Fatty Acids (SFA) and Mono Unsaturated Fatty Acid (MUFA) (P < 0.05). Feed intake and WG were reduced on 30 and 45% diets (P < 0.05). Fat digestibility was improved on control and 30% CM diets with enzyme (P < 0.05). Higher WBC counts were recorded in control and 15% CM with enzyme (P < 0.05). Higher SFA and lower MUFA were on 15 and 45% diets (P < 0.05). In the main effects, feed intake and weight gain (WG) were reduced and feed conversion ratio (FCR) increased with increasing level of CM above 15% (P < 0.05). The diet with 45% CM showed lower SFA (P < 0.05) compared to 15% CM diet, MUFA and PUFA reduced with increasing CM levels (P < 0.05). Enzyme supplementation reduced SFA and MUFA content (P > 0.05) but improved crude fibre and fat digestibility of broilers (P < 0.05). In conclusion, 30% dietary CM inclusion is detrimental in terms of WG but has no effect on the fatty acid composition of broiler meat. More research into enzyme source and concentration above 30% CM is recommended.
Proceedings, Volume 36; doi:10.3390/proceedings2019036201
Growth, development and yield of three-grain legumes (mung bean [F1], soybean [F2] and grass pea [F3]) following rice crop to enhance grain production was studied in a paddy field in the northern Timor-Leste. A split plot design was used with three water treatments (well-watered [W0], water withheld at flowering [W1] and after germination [W2]). Interaction between water treatments and species on dry matter production (p < 0.001) and seed yield (p = 0.005) was observed. In control, the highest seed yield was F1 (1.2 t/ha) followed by F2 (1.1 t/ha) and F3 (0.4 t/ha) respectively. There was a steady reduction in seed yield in F1 from W0 to W2, but almost fifty percent reduction in F2 under W1 and W2 compared to W0. F3 had little difference between water treatments. The W1 and W2 reduced number of filled pods per plant in all species compared to control (W0). Between the species, F3 had the highest filled pods per plant followed by F2 and F3. The W1 and W2 reduced seeds per pod of F1; however, it did not effect F2 and F3. There were interactions between water treatment and species on 100 seeds weight. The heaviest seeds were in F2 in the control plants, but in the F2 drought treatments (W1 and W2) seed weight were less than F3. The lowest seed weight was in F1, but there was no impact of the terminal droughts on its seed weight.
Proceedings, Volume 36; doi:10.3390/proceedings2019036202
The low cropping intensity in the southwestern coastal Bangladesh is constrained by excess wetness of soil, low fertility and scarcity of fresh irrigation water. Fallow-fallow-T. aman is the main cropping pattern in this region. In the recent years some winter (dry season) crops (wheat, sunflower, maize etc.) have been introduced. Among them sunflower is best suited as it can be established in wet soil and also having the capacity to tolerate salinity and drought to some extent. The fertility of soil of this area is low particularly nitrogen (N). There is no fertilizer recommendation for sunflower in this area. Thus it is necessary to develop a fertilizer recommendation for sunflower. To develop this, a set of field experiments were carried out during winter season (2018–19). In these experiments, the major nutrients [nitrogen (N), phosphorus (P) and potassium (K)] were varied in early (by November) and late (end of December) sown (dibbled) sunflower. Results showed that early sown sunflower produced higher seed yield with lower amount of N than that of late one. In case of P, unlike N, yield increase was not at par with the increase of P rates indicated residual P that applied to previous rice crop supported the sunflower. Potassium rates have little effect on yield increase. Based on the average yield (~3.5 t/ha) of the variety (Hysun-33) N, P and K @ 120–150, 40–50 kg/ha and 50–60 kg/ha was produced highest yield in early sown sunflower in excessively wet soil of southwestern coastal Bangladesh.
Proceedings, Volume 36; doi:10.3390/proceedings2019036203
C4 plants play a key role in world agriculture and strategies to manipulate and enhance C4 photosynthesis have the potential for major agricultural impacts. The C4 photosynthetic pathway is a biochemical CO2 concentrating mechanism that requires the coordinated functioning of mesophyll and bundle sheath cells of leaves. Chloroplast electron transport in C4 plants is shared between the two cell types; it provides resources for CO2 fixation therefore underpinning the efficiency of photosynthesis. Using the model monocot C4 species Setaria viridis (green foxtail millet) we demonstrated that the Cytochrome (Cyt) b6f complex regulates the electron transport capacity and thus the rate of CO2 assimilation at high light and saturating CO2. Overexpression of the Cyt b6f in both mesophyll and bundle sheath cells results in a higher electron throughput and allows better light conversion efficiency in both photosystems. Importantly, increased Cyt b6f abundance in leaves provides higher rates of C4 photosynthesis without marked changes in Rubisco or chlorophyll content. Our results demonstrate that increasing the rate of electron transport is a viable strategy for improving the light conversion efficiency in C4 crop species like maize and sorghum.
Proceedings, Volume 36; doi:10.3390/proceedings2019036204
Sucrose and fibre in sugarcane share a very dynamic relationship depending largely upon the genetic makeup of the genotypes and growth environment. To investigate the molecular basis of carbon flux into sucrose and fibre that makes the genotypes high sugared or high fibred, or dual purposed, an extensive transcriptomics study was undertaken using a set of sugarcane genotypes differing in sugar and fibre contents. Differential gene expression analyses were performed using 50 transcriptomes revealing a complex network of transcripts associated with growth, defence, vacuole, sucrose and fibre. Rather than merely being a storage sugar of the culms, sucrose might play a significant regulatory role in controlling the expression of several thousand genes including those related to fibre. The high sugar genotypes were not always low in fibre and the fibre might to an extent provide structural framework for maintaining high sugar levels as seen by the high expression of fibre related genes. The study suggests that there could exist certain threshold levels of sugar or fibre contents beyond which an inverse relation would occur. In addition, analysis of the transcriptomes resulted in the identification of a new isoform of sucrose synthase genes, SuSy 7 that was not reported earlier. With the availability of a monoploid reference genome, there is a need for in-depth transcriptome studies to understand and identify finer details of genes, and their transcripts in entirety and regulatory elements of sugarcane genome which is challenging the current capabilities of sequencing technologies unlike any other plant genomes sequenced thus far.
Proceedings, Volume 36; doi:10.3390/proceedings2019036205
Giant taro (Alocasia macrorrhiza var. Tonga) grows wild in Pacific Island countries and has become invasive in most countries. Proximate analysis of giant taro (GT) corm at USP Alafua Central Laboratory showed ~12 MJ ME/kg, 127 g crude protein/kg DM. Currently however, the crop has low food value in the region and its use in poultry feeding is still limited because of the acrid taste due to the presence of calcium (Ca) oxalate. Two preliminary studies (PS) were conducted to evaluate the feeding value of GT for poultry. Study 1 investigated the effect of coconut oil addition on the utilsation of GT corm meal by layers and broilers. Replacing dietary maize with whole GT corm meal at 200 g/kg adversely affected performance of broilers and layers (P < 0.05). Addition of coconut oil at 9:1 (corm meal: oil) improved utilisation of the meal by laying hens but not in broilers. Study 2 investigated the effect of peeling and inorganic calcium addition on the utilisation of GT corm meal by laying hens. Results showed that feeding whole GT corm meal at 200 g/kg diet had adverse effects on egg production and egg qualities (P < 0.05) but peeling or increasing dietary Ca carbonate level from 40 to 60 g/kg improved the utilisation of whole or peeled corm in terms of egg production and egg qualities. In view of the ready availability and low food value, more research is recommended into processing and diet formulation to improve the utilsation of GT corm meal by poultry.