Plant Maturity Affects Flowering Ability and Flower Quality in Phalaenopsis, Focusing on Their Relationship to Carbon-to-nitrogen Ratio

In the commercial production of phalaenopsis orchids, the cultivation time after deflasking is used to describe the plant age and maturity. Carbon-to-nitrogen (C/N) ratio is often used as an indicator of plant growth and flowering potential. High C/N ratios are considered to promote reproductive growth, and low C/N ratios are associated with the early vegetative growth or even inhibiting flowering. This study investigated how plant age and maturity affected flowering ability and flower quality of phalaenopsis and their relationship to C/N ratio. The plant materials of various ages were the purple, small-flowered Phalaenopsis Sogo Lotte ‘F2510’ and white, large-flowered P. Sogo Yukidian ‘V3’, which were 2 to 7 months and 10 to 20 months after deflasking, respectively. Plants were placed under 25/20 °C for 4 months to force flowering and investigate the flowering-related parameters. The leaf C/N ratio of both varieties increased in general with the increase of plant age. The spiking (flower-stalk emergence) rate of P. Sogo Lotte ‘F2510’ 2 months after deflasking was only 42%, which indicates that these plants were not completely out of their juvenile phase, whereas that of those 3 to 7 months after deflasking was 100%, indicating that plants had acquired full flowering ability. No linear correlation was found between the C/N ratio and days to spiking, to first visible bud, to first flower open, and to 90% flower opening in the white, large-flowered P. Sogo Yukidian ‘V3’. However, there was a positive correlation between the C/N ratio and inflorescence length, flower-stalk diameter, first flower diameter, and flower count. Thus, the C/N ratio is feasible to be used as an indicator for assessing the flowering quality in phalaenopsis.

Comparative analysis of infection process in Pima cotton differing in resistance to Fusarium wilt caused by Fusarium oxysporum f. sp. vasinfectum race 4

Fusarium oxysporum f. sp. vasinfectum race 4 (FOV4) causes an early season cotton disease including seedling deaths. This study compared two Pima cottons (Gossypium barbadense) in the infection process of FOV4 using a confocal and a scanning electron microscope. Seedlings were grown in a hydroponic system and inoculated with a virulent local FOV4 isolate. As compared to the susceptible Pima S-7, the resistant Pima PHY 841 RF had significantly fewer conidia attached and germinated on the root surface. FOV4 penetration into the root epidermis of PHY 841 RF was delayed until 24 hours post-inoculation (hpi), as compared to 8 hpi in Pima S-7. In Pima S-7, hyphae progressed to the xylem through the cortex between 5 and 7 days post-inoculation. However, hyphae grew much slower in the cortex with no apparent hyphae observed in the xylem of PHY 841 RF. At plant maturity, no FOV4 was detected through fungal isolation and PCR in the stem of PHY 841 RF and its resistance donor parents PHY 800 and Pima S-6, as compared to Pima S-7 and DP 744 with positive results.

Improving the productivity of okra (Abelmoschus esculentus L.) by strengthening the impact of applied nutrients through alligator weed compost

Weeds produce huge biomass by competing with the main crop for resources has been well established by numerous investigators. The use of weeds, especially aquatic weeds, as an organic source of nutrients such as compost is lacking in the literature. We hypothesized that the use of aquatic weeds i.e. alligator as compost would limit the use of inorganic fertilizers in okra and it would increase the quality of produce. To maximize the effect of inorganic nutrients, it would be easier to use the alligator weed compost as a natural source of nutrients. The crop was sown on 22 July, 2017 and 20 July, 2018 in a randomized complete block design having four replications. The net plot size was 1.8 m x 6 m. The alligator weed compost along with NPK was applied at the time of sowing. Alligator weed compost was applied along with different combinations of NPK i.e. control (recommended dose of NPK 159-114-93 kg ha-1 ), compost application of 250 kg ha-1 , compost application of 500 kg ha-1 , compost application of 250 kg ha-1 with 75% recommended NPK, compost application of 250 kg ha-1 with 50% recommended NPK, compost application of 250 kg ha-1 with 25% recommended NPK, compost application of 500 kg ha-1 compost with 75% recommended NPK, compost application of 500 kg ha-1 with 50% recommended NPK and compost application of 500 kg ha-1 with 25% recommended NPK. Compost application of 250 kg ha-1 with 50% recommended NPK significantly reduced the number of days to flowering and increased plant height (cm) at flowering and plant maturity over the alone NPK and other combinations of compost and NPK. Pod yield and yield components were outclassed by the compost application of 250 kg ha-1 with 50% recommended NPK over the other combinations. For example, number of pods per plant and pod yield (t ha-1 ) were increased by 26%, 20%, respectively averaged across during both years of study over the recommended dose of NPK alone. Similarly, application of compost at 500 kg ha-1 along with NPK 50% of recommended dose enhanced pod potassium and ascorbic acid contents by 76% and 35%, respectively averaged across during both years of study over the control dose of NPK. Conclusively, alligator weed organic source of nutrients could reduce NPK fertilizers as it holds the nutrients applied and also provides the essential nutrients. In future climates, alligator weed compost would be a sustainable and environment friendly approach.

Evaluation of Traits’ Performance Contributing to Drought Tolerance in Sorghum

Sorghum (Sorghum bicolor [L.] Moench) is an important food crop for people in semi-arid Africa. The crop is affected by post-flowering drought; therefore, the study was conducted to screen traits contributing to drought tolerance using BC2F4 sorghum genotypes in stressed and unstressed water conditions in a split-plot design. Water stress (0 mm/day) was applied at post-flowering to plant maturity in water-stressed treatment. The genotype SE438 produced the highest grain yield (2.65 ton ha−1) in water-stressed environment and NA316C yielded highest (3.42 ton ha−1) under well-watered (7 mm/day) environment. There were significant differences of most traits evaluated at p < 0.01 across environments. The mean squares of traits for genotypes by environments revealed interactions at p < 0.05 and p < 0.01. The indices geometric mean productivity (GMP) and mean productivity (MP) were highly correlated with yield under well-watered (YP) and water-stressed condition (YS) and each other. The first principal axis (PC1) explained 59.1% of the total variation. It is the best indicator of yield potential and drought tolerance of sorghum genotypes in this study. Therefore, further improvement is needed to strengthen drought tolerance and yield in sorghum.

Effect of Different Water Quality on the Nutritive Value and Chemical Composition of Sorghum bicolor Payenne in Cape Verde

Cape Verde is a semiarid country where lack of rainfall exacerbates the scarce resources available for livestock which, therefore, make it very vulnerable to climate change. By providing reclaimed water (RW) for irrigation, it is possible to decrease forage importation. Subsurface drip irrigation (SDI) improves health security by preventing contact between water and harvested plants. Sorghum is a water-efficient crop that provides good nutritional value. The aim of this experiment was to study the nutrient and fiber contents of the Sorghum Payenne variety using subsurface (T1) and surface (T2) drip irrigation by RW vs. conventional water (T3) and plant maturity to assure the feasibility of water reuse to produce forage. Ntot–Ptot–Ca–Mg and Na were significantly higher in the RW plants than in the conventional water ones. Ntot–Ptot–K and Fe contents significantly lowered, while Ca–Na and Mn significantly rose as plant maturity increased. All the fiber values meet the Nos. 2 and 3 quality standards, and the Prime and No. 1 for NDF and ADF, respectively. The obtained good forage quality let to avoid the competence of conventional water and to reuse nutrients added by RW. If generalized, this solution would reduce forage importation by improving food sovereignty and farmers’ profitability, and would enhance resilience against climate change effects.

Spontaneous Gene Flow between Cultivated and Naturalized Vicia villosa Roth Populations Increases the Physical Dormancy Seed in a Semiarid Agroecosystem

Hairy vetch (Vicia villosa Roth) is the second most cultivated vetch worldwide being used as a forage and cover crop. As it is not domesticated, it displays several wild traits including seed dormancy. The physical seed dormancy (PY) variation could be useful depending on the specific context. High PY is desirable for ley farming systems, while low PY is needed to prevent weediness in subsequent crop rotations. Gene flow between cultivated and naturalized populations has important ecological and agronomic consequences. Experiments were conducted to determine the change in the level of PY in spontaneous crosses between European cultivated accessions (EU) characterized by low PY and naturalized Argentinian population (AR) with high PY. Generations G0 (initial generation) to G3 were assessed for their PY in seeds and total dry matter (DM) per plot, at plant maturity. As the result of spontaneous crosses with the AR population, an increase from G0 to G3 in PY and DM in EU accessions was observed, while AR maintained its high PY and DM values. In one mating cycle, selecting for PY lower than 14% and high DM can satisfy breeding objectives for cover crops. Isolation during breeding and seed production is necessary to avoid gene flow. This knowledge extends to other legume species with gene flow between wild and cultivated populations.

Responses and screening of white jute (Corchorus capsularis L.) genotypes against salinity stresses

Soil salinity, a serious threat to jute cultivation in saline areas (southern parts) of Bangladesh. Bangladesh Jute Research Institute (BJRI) has developed a moderately salt tolerant White Jute variety (BJRI Deshi pat-8; BJC 2197) in 2013 which can’t grow well in saline areas having more than 8.0 dSm-1 salinity stress. Hence, 23 whitejute accessions and one control variety (BJC 2197) were tested to isolate the salt tolerant accession(s) for hybridization purpose followed by augmented design in farmers’ field having nearly 8.0-9.0 dSm-1 salinity at Patuakhali district during mid-March to mid-August 2019. The experimental plot size was 3.0 m2 (3 m × 1 m) for each genotype having 3 lines of 1.0 m length, plant-plant: 10-15 cm and line- line: 30 cm distance. Soil salinity was recorded during sowing, vegetative and plant maturity stages. In this study, the highest plant height 2.84 m was recorded in Acc. 2750 followed by Acc. 2589 (2.76 m) and Acc. 1779 (2.69 m). The highest fiber yield (9.0 g plant-1) was observed in Acc. 1779 followed by Acc. 2589 (8.40 g plant-1) and Acc. 2750 (8.0 g plant-1). The lowest plant mortality rate (2.5%) was found in Acc.2750 followed by Acc.1779 (6.24%), Acc. 1780 (7.50), Acc. 3556 (11.10%), Acc. 2589 (11.20%) and BJC 2197 (16.5%). Few seeds were germinated in Acc. 3020 and Acc. 3658 but plants were died after 20 days of sowing. Six genotypes of cluster I showed higher diversity in Euclidean cluster analysis. The Acc. 2750, Acc. 1779, Acc. 2589 of cluster I having relative salinity tolerance and good fiber yield capacity would be grown in next year for confirmation as well as hybridization with the existing salinity susceptible variety to develop high yielding white jute variety for saline areas.

Effects of Harvest and Fertilization Frequency on Protein Yield and Extractability From Flood-Tolerant Perennial Grasses Cultivated on a fen Peatland

Paludiculture, and in particular the cultivation of perennial grasses as biomass feedstock for green biorefineries, may be an economic and environmentally sustainable option for agricultural peatlands in temperate regions. However, the optimal biomass quality for protein extraction from flood-tolerant grasses is largely unknown. The aim of this study was to define the combined effect of harvest and fertilization frequency, with one to five annual cuts, on protein yield and extractability for the grasses tall fescue (TF) and reed canary grass (RCG), cultivated on an agricultural fen peatland in Denmark.The content of protein fractions was determined according to the Cornell Net Carbohydrate and Protein System (CNCPS). We assessed protein extractability by lab-scale biorefinery techniques using a screw-press followed by acid precipitation of true protein. The two methods were compared to correlate potential extractable protein yields with actual biorefinery outputs. We found the highest annual biomass and crude protein (CP) yields in the two cut treatments, with 13.4 and 15.6 t dry matter (DM) ha−1 year−1, containing 2.9–3.4 t CP ha−1 year−1 for TF and RCG, respectively. The highest neutral-extractable (fractions B1 and B2) true protein yields of 1.1 and 1.5 t ha−1 year−1 were found in the two cut treatments, representing 39% (TF) - 45% (RCG) of total CP. Using biorefining techniques, we were able to precipitate up to 2.2 t DM ha−1 year−1 of protein concentrate, containing up to 39% CP. Significant correlations between methods were found, with a distinct relationship between CNCPS fractions B1 + B2 and CP yield of the protein concentrate, indicating the suitability of the CNCPS as an indicator for extractable protein yields. Biomass and CP yields were not significantly improved beyond two annual cuts. However, timing and harvest frequencies significantly affected plant maturity and consequently extractable CP contents and protein concentrate yields. We conclude that TF and RCG are promising feedstocks for green biorefineries due to high biomass, extractable CP, and protein concentrate yields, and highlight the potential of flood-tolerant grasses, cultivated on wet agricultural peatlands, for an enhanced valorisation beyond the common utilisation for bioenergy.

Yield Response of Determinate Chipping Potato to Artificial Defoliation

The relationship between canopy defoliation by insects and yield loss in potato (Solanum tuberosum L.) has been extensively researched. However, detailed analysis of varieties with different properties and examination of methods of defoliation are still lacking. Absence of research results has led many producers to use a very conservative economic threshold (ET) of 10% defoliation in the management of insect defoliators. A series of leaf removal experiments was conducted on a determinate chipping variety of potato at different plant stages. In 2002, the highest levels of defoliation induced upon the plant canopy were 50, 30, and 75% for tuber initiation, full bloom, and plant maturity stages, respectively. In 2003, defoliation levels were increased to 70, 80, and 90% for tuber initiation, full bloom, and plant maturity, respectively. Total yield was unaffected, and no significant changes in market sized yield, or number of marketable tubers were observed at any growth stage in either year. Because the determinate variety showed remarkable ability to recover from substantial defoliation, two different methods of defoliation: hand cut (cutting the edge of leaves with scissors while avoiding the midrib) and hole punching (hole-punching leaf tissue [15.08-mm diameter] while avoiding midrib) were tested. Although total yield was unaffected, marketable yield and small potato yield were reduced, Thus, although defoliation methods must be considered, a 10% defoliation ET is exceedingly conservative and an ET of 60% for all stages of determinate chipping potato could be adopted by growers.

Complementary Transcriptome and Proteome Analyses Provide Insight into the Floral Transition in Bamboo (Dendrocalamus latiflorus Munro)

Most woody bamboos bloom only once after long vegetative growth phases and die immediately afterwards. It is difficult, however, to determine the timing of the floral transition, as little information is available on the molecular mechanism of plant maturity in bamboos. To uncover the bamboo floral transition mechanism, its morpho-physiological characteristics, transcriptomes and large-scale quantitative proteomes were investigated in leaves which were collected at different stages during floral transition in a woody bamboo, Dendrocalamus latiflorus. We identified many flowering time-associated genes and the continued increase and decrease genes were screened as flowering biomarker genes (e.g., the MADS14 and bHLH13 genes). These different genes were assigned to specific metabolic pathways by the Kyoto Encyclopedia of Genes and Genomes (KEGG). And the photoperiod pathways depending on the circadian rhythm may play an essential role in the bamboo floral transition. In addition, a total of 721 differently expressed proteins of leaves from the vegetative-to-reproductive stages were identified. Fifty-five genes were specifically differentially expressed at both the transcriptomic and proteomic levels, including genes related to photosynthesis and nucleotide sugar, which may be involved in the floral transition. This work provides insights into bamboo flowers and the management of forest breeding.