Short-cycle Crops Research Articles

Head Loss in Thin-Walled Drip Tapes with Continuous Labyrinth.

Thin-walled drip tapes with continuous labyrinth have been used for irrigation of vegetables and other short-cycle crops, especially due to their low cost. The continuous labyrinths welded into the pipe inner wall affect the head loss along such emitting pipes. In addition, the flow cross section of thin-walled pipes may change due to the effects of the operating pressure, which also has consequences for the head loss. The objective of this work was to investigate experimentally the friction factor and the head loss on thin-walled drip tapes with continuous labyrinths operated under various pressures. Two models of commercial thin-walled drip tapes with continuous labyrinths were evaluated. Nonperforated samples were used to determine the head-loss equations. The equations were adjusted as a function of flow rate and pressure head at the pipe inlet. Alternatively, the diameter in the Darcy–Weisbach equation was adjusted as a function of the pressure head by a power-law model. The possibility of using a mean diameter in the Darcy–Weisbach equation was also analyzed. Experimental investigation indicated that the friction factor in the Darcy–Weisbach equation can be accurately described using a power-law model, like the Blasius equation, but characterized by a coefficient a=0.3442 for the Turbo Tape and a=0.3225 for the Silver Tape. The obtained values of a are larger than those generally used and available in the literature. The influence of the operating pressure on the pipe diameter can be neglected for the purpose of calculating the head loss. The two approaches, considering the variation of the diameter with the pressure head and considering an optimum average diameter for the calculation of head loss by the Darcy–Weisbach equation, produce similar results, allowing accurate prediction of head loss. Evaluating the proposed mathematical models, 95% of predictions presented relative errors of head loss smaller than 5%. For the Turbo Tape, the optimum diameter for the purpose of calculating the head loss is 16.01 mm, which is very close to the value indicated by its manufacturer (15.9 mm). For the Silver Drip, the optimum diameter is 15.71 mm, while the manufacturer gives a value of 16.22 mm, which produces considerable error in the calculation of head loss.

Review of Potato Research and Development in Ethiopia: Achievements and Future Prospects

Root crops are good sources of food, cash and foreign exchange for the majority of smallholder farmers in Ethiopia. Among root and tuber crops, potato is an important food and cash crop in Eastern and Central Africa, playing a major role in national food and nutrition security, poverty alleviation and income generation, and provides employment in the production, processing and marketing sub-sectors. In Ethiopia, potato production has increased during the “Meher” season as a result of improved varieties, being tolerant to major potato disease, late blight especially in the areas of major potato growing regions of the country. It is a short cycle crop with three to four months cropping cycle, are well suited to double cropping particularly in rain-fed systems and has significant advantage over grain crops which require relatively longer time to mature. Its short growing cycle allows for flexible planting and harvesting times and also permits quick production of foods to augment “hunger months” of August to October before grain harvests when people lack sufficient food to meet their basic caloric and nutritional requirements. The potato crop is cheap but nutritionally rich staple foods that contribute carbohydrates, protein, vitamin C, vitamin A, zinc, iron and minerals which alleviate the problem of malnutrition in subsistence farming areas and towards the dietary demands of the country‘s fast-growing towns and cities. Another advantage of this crop is that, it is largely traded locally and nationally, as opposed to internationally. The crop is far less susceptible to large-scale market shocks and price speculations experienced by more widely traded staples, such as grains, during international market crises. As such, it contribute to a more stable food system, maintain nutritional and food security, and are a predictable source of income. To exploit the potential benefit of this valuable crops as food and nutrition security, the Ethiopian Agricultural Research Institute (EIAR) through its implementing federal and regional research centers has been conducting several research and development activities on potato since its establishment in 1966. Since then several technologies have been released, demonstrated and popularized for the larger farming community in the country. The objective of this paper is, therefore, to review potato research and development outputs obtained so far, potentials and opportunities as well as challenges and research gaps for potato production and productivity in the country. Keywords: Potato; food & nutrition security; achievements; technologies; Ethiopia DOI : 10.7176/JBAH/9-19-04 Publication date :October 31 st 2019

Effect of fertigation using fish production wastewater on Pelargonium x zonale growth and nutrient content

Aquaculture effluent can supply certain plant nutrients in adequate amounts. However, the nutrients present in the fish waste solution are not balanced. Mixing this effluent in an independent unit with a hydroponic nutrient solution can help to optimize conditions for the plants and minimize such drawbacks. The objective of this work was to assess the crop production and the nutritional responses of Pelargonium zonale fertigated with different percentages of fish wastewater. Five treatments were performed: 100NS, 75NS + 25AS, 50NS + 50AS, 25NS + 75AS and 100AS, where AS is the fish wastewater and NS a hydroponic nutrient solution. The species used to provide the fish waste solution was tilapia nilotica (Oreochromis niloticus). The results of this assay show that: i) fish wastewater can be utilized for the fertigation of Pelargonium zonale (a short-cycle crop) as there are no differences in the leaf, stem-petiole and flower dry matter, leaf water content, leaf area, plant height and leaf color compared to Pelargonium zonale fertigated with a chemical fertilizer; ii) the application of 75NS + 25AS accelerated flowers, shoots and leaves production. A higher percentage of fish waste solution mixed with the applied nutrient solution significantly reduces the K concentration in the nutrient solution and in the leaf; however, tilapia waste solution supplies adequate N, P and Ca nutrients to the pelargonium plants. Therefore, the reuse of fish waste solution can reduce the application rate of some inorganic fertilizers, which in turn can reduce the cost of fertilizers while preventing environmental pollution.

Role of Nitrogen on Potato Production: A Review

Potato (Solanum tuberosum L.) is a perennial plant of the Solanaceae family and the world’s most important and widely grown tuber crop ranking fourth after rice, wheat and maize. In terms of human consumption, it ranks third after rice and wheat. It could be one of the most important crops to be introduced in the area where the population experiences recurrent malnutrition due to heavy dependence on cereal crops and poor crop productivity for the reason that its ability to provide a high yield of high-quality product per unit input with a shorter crop cycle as compared to the major cereal crops. To increase potato production Nitrogen (N) among others is the mineral nutrient most commonly deficient in agricultural soils. The optimal response to N fertilizer application differs by cultivar and soil type; hence it needs critical consideration for different cultivars at specific location. Fertilizer requirement varies across locations due to numerous reasons such as difference in soil types, nutrient availability of the soil, economic factors of the area, moisture supply and variety. Ensuring the optimum husbandry including nutrient management is very important because soil-plant system inefficiencies prevent complete utilization of the N, leaving residual N in the soil, which is a waste of natural resources and cause for environmental concern. This needs due attention since the crop demands high level of soil nutrients due to relative poorly developed and shallow root system in relation to yield. Generally, concerning nutrient, optimum yield can be obtained by improving nutrient management (provided that other issues e.g. improved variety are fulfilled) since tuber yield and tuber quality are directly impacted by quantity and timing of nutrient applications. Split application (each on a vital time) of N is important in order to avoid loses through leaching, volatilization, denitrification, utilization by weeds, erosion by running-off water and sedimentation.

RESIDUOS DE PLAGUICIDAS EN SUELOS DE USO AGRÍCOLA Y RIESGO DE EXPOSICIÓN EN LA MICROCUENCA LOS ZARZALES, MUNICIPIO RIVAS DÁVILA, ESTADO MÉRIDA, VENEZUELA

There is a growing concern about the presence of pesticide residues in agricultural land because they constitute an environmental risk and a source of human exposure. In this work, the presence of these residues and the risk of exposure was determined in the micro-watershed of Los Zarzales, Rivas Davila municipality, Merida, Venezuela. Soil samples were taken in the initial, middle and final stages of short cycle crops, and the active ingredients were extracted and analyzed by HPLC. The risk of exposure was estimated by calculating the dose of pesticides through non-dietary intake of contaminated soil and dust, according to the US-EPA criteria. The highest concentration and variety of compounds was recorded during the middle stage: 26 ± 7 mg/kg of total residues and 100% detection frequency, standing out among them paraquat (15 ± 7 mg/kg), carbendazim (8 ± 2 mg/kg), mancozeb (3.7 ± 0.7 mg/kg) and carbofuran (1.2 ± 0.5 mg/kg). Based on these values, the calculated daily doses were 1.5, 0.8, 0.37 and 0.12 μg/day, respectively, all of which were below the admissible daily intake established by FAO/WHO, which is used as reference. Despite of this, the total dose reached 2.8 μg/day, which is considered as a risk of exposure.

Intercropping Pineapple With Rice or Cowpea: An Alternative for Family Farming in the State of Tocantins, Brazil

Pineapple is commonly planted in monoculture systems. It is a long-cycle crop that takes time to monetize, which hinders its cropping by small farmers. The objective of this work was to evaluate the production and quality of pineapple with short-cycle crops, at the beginning of the growing period, as an alternative for family farming in the state of Tocantins. The experimental design was randomized complete block with three treatments and four replications. The pineapple was intercropped with rice and cowpea. The treatments consisted of T1: pineapple + rice; T2: pineapple + cowpea and T3: pineapple in monoculture. The evaluated variables of the pineapple fruit were pH, soluble solids, titratable acidity, yield, fruit mass, fruit length with crown, fruit length without crown and fruit circumference. For the rice and cowpea, the yield and the Area Equivalence Index (AEI) were determined. The cropping system did not influence the pineapple fruits quality. The pineapple yielded less. Cowpea yielded more when intercropped with pineapple. The AEI of the pineapple + rice intercropping was 2.07, being feasible for increasing the use of the area by 100%. The AEI of the pineapple + cowpea intercropping was 2.48, being feasible as it increased the use of the area by 148%. The results obtained showed that it is possible to intercrop pineapple with rice or cowpea at the beginning of pineapple cultivation, and it can be a viable alternative for family farming.

Restoring Ecological Functions Using Agroforestry Systems in Riparian Forests

ABSTRACT Agroforestry systems and restoration models were compared with native forests by examining the restoration of ecological processes that generate stability, resilience and reliability. The stability assessment was obtained using indicators of diversity, structure and functionality. Indicators of soil protection and nutrient cycling were also used to estimate the resilience. The reliability was assessed by management and protection indicators, anthropic impact and canopy (percentage of light). Agroforestry systems did not promote the restoration of ecological functions due mainly to structural factors than management. The production of biomass and carbon storage were higher in the agroforestry system considering the association of trees with short cycle crops (3.2 t ha-1 yr-1; 39.81 t C ha-1) than trees with green manure system (2.4 ha-1 yr-1; 34.09 t C ha-1). After 36 months, the restoration methods and agroforestry systems did not provide resilience and stability for the riparian forests protection.

Agronomic practices with a special focus on transplanting methods for optimum growth and yield of enset [Ensete ventricosum (Welw.) Cheesman] in Ethiopia

Introduction - Transplanting enset suckers or plants is practiced by the majority of small-scale farmers across the enset-growing belt in Ethiopia. Enset suckers, obtained from a multiplication nursery, are first intensely managed in a small plot (one plant 0.5-1.0 m(-2)) from where plants are consecutively transplanted into ever more widely spaced arrangements with a final minimal spacing of one plant 2-4 m(-2). This review summarizes relevant information on transplanting methods from randomized controlled field trials and on-farm observations. Results and discussion - Transplanting frequency impacts the crop cycle duration and yield. Transplanting once results in plants with a higher growth rate and hence a shorter crop cycle, while more frequent transplanting results in higher yields per plant. For example, plants transplanted once were harvested at 2 years and yielded 27 kg dry matter (DM) plant(-1), while plants transplanted two or three times were both harvested at 4.5 years and yielded, respectively, 44 and 31 kg DM plant(-1). Conclusion - This review endeavours to help determine the enset transplanting methods that give optimum growth, biomass production and yield.

Scaling up of tigershrimp (Penaeus monodon) production in brackishwater pond under diversified cropping regimes

To develop a scientific and affordable shrimp farming system for marginal to medium farmers with low inputs and higher returns by scaling up of production per unit area, shrimp culture was practiced with 3, 5 and 7/m2 stocking densities for the period of 60 days as short cycle and 120 days as long cycle. All the hydrographical parameters were found congenial in different treatments except dissolved oxygen (DO) in case of higher stocking density and long culture pattern. However, the specific growth rate (SGR) was optimal in both culture cycle but increased sharply in first 3-4 weeks of grow out period. Distinct survival rate were found in different treatment which was ranged from 86.39 to 90.96% but did not show significant difference (P>0.05%) among the treatments of short and long culture cycle. Total yield was ranged from 990 kg/ha to 1998 kg/ha for short cycled double and 1012 kg/ha to 2032 kg/ha for single cropping pattern. Highest production was obtained under the stocking densities of 7/m2although the average production showed significant difference (P<0.05%) among the treatments of both culture patterns. The food conversion ratio (FCR) value seems similar for all cropping patterns and ranged between 1.15 and 1.57. Except stocking density of 7/m2 at short cycle culture, net benefit were significantly (P>0.05%) higher in long cycle crop than that of aggregate of two short cycle crops. But benefit cost ratio (BCR) in short culture cycle is significantly (P>0.05%) higher than that of long culture (120 days) which indicates higher net benefit as well as positive feasibility of short culture system. Considering the infrastructural facilities in farm level and resource capability, this shrimp farming technology would be appropriate to boost up the production and income particularly for marginal to medium farmers.Asian J. Med. Biol. Res. March 2018, 4(1): 27-35

Morphological, biological, productive and qualitative characterization of 68 guar (Cyamopsis tetragonoloba (L.) Taub.) genotypes

Guar (Cyamopsis tetragonoloba (L.) Taub.) is a valuable industrial crop, widely cultivated in India and Pakistan for the high galactomannan content of its endosperm. The present multi-trait characterization of 68 guar genotypes was conducted to identify an ideotype combining desirable traits suitable for cultivation in a Mediterranean climate and that allows an easy harvest. Plant height, branch number, stem diameter, length of crop cycle, number of cluster, number of pods per plant, number of seeds per pod, 1000 seeds weight, seed production per plant, galactomannan and protein content were measured. In addition, correlations between morphological and productive traits were applied, calculating the relationships between traits, and giving biological meaning to the ideotype. To select high performance genotypes under Mediterranean climate, we mainly took into consideration non-branching (easy harvestability, uniformity of maturation) and short crop cycle genotypes with valuable productive and qualitative traits. From this viewpoint, the results showed that 17 genotypes resulted non-branching, 11 genotypes showed a short crop cycle and seven genotypes were characterized by a seed production greater than 50 g plant−1. Four of the 17 genotypes (PI 288757, PI 340263, NC70300525and PI 288745) possess all these desirable traits along with good seed production and therefore should be selected as multi-trait high performance genotypes. As far as the galactomannan and protein contents are concerned, a lower coefficient of variation emerged when compared to those of the morphological or productive traits. Correlation analysis showed that plant production was related to cluster number, number of pods per plant, seeds per pod, number of branches and length of crop cycle. Finally, an interesting negative association between galactomannan and protein content was found.

Pleurotus djamor, un hongo con potencial aplicación biotecnológica para el neotrópico

Antecedentes: Pleurotus djamor es un hongo pantropical, cultivado comercialmente en algunos países asiáticos. Debido a sus características de crecimiento, ciclos de cultivo cortos y aceptable valor nutrimental, es una especie comestible adecuada para su propagación y consumo en las regiones cálidas del mundo.Objetivo: El propósito de la presente revisión fue conocer los avances en la biología y cultivo de esta especie, con la finalidad de incrementar su potencial aprovechamiento en el neotrópico.Método: Se hizo una revisión bibliográfica del tema, seleccionando información relevante sobre aspectos biológicos y biotecnológicos de la especie.Resultados y conclusiones: Esta contribución revisa las características nutrimentales y funcionales de la especie, así como sus capacidades biosínteticas y biodegradativas en diversos procesos biotecnológicos, tales como producción de alimento, biotransformación de residuos orgánicos a través de la secreción de enzimas ligninocelulolíticas y su aplicación en procesos de biorremediación de suelos y agua, entre otros. P. djamor ha sido utilizado exitosamente en diferentes procesos biotecnológicos y representa un hongo comestible alternativo para el neotrópico, debido a las condiciones ambientales y disponibilidad de materiales lignocelulósicos existentes. La producción y consumo de esta especie podría mejorar las condiciones nutrimentales, ambientales y económicas de los pobladores de esta región.

Fisiologia do rabaneteiro em diferentes arranjos espaciais

Radish (Raphanus sativus L.) is a short cycle crop, providing rapid economic return to the producer. For its appropriate cultivation, the definition of aspects related to the field implantation, the choice of the ideal crop spacing combined with the density of plants per hole, and the understanding of its effects on the physiology of the crop, help to obtain maximum productive efficiency. Thus, this study sought evaluate the physiological performance of radish plants subjected to different spatial arrangements between plants and plant density per hole. For such, an experiment using a randomized block design was conducted, with four replicates, in a 4 × 2 factorial scheme. The first factor was composed of four different plant spacings (0.05; 0.10; 0.15; 0.20 m) and the second by two cultivation densities (one and two plants per hole). Internal CO2 concentration, transpiration, stomatal conductance, liquid photosynthesis, ratio between environment and internal CO2 concentration, instantaneous carboxylation efficiency, gross photosynthesis, chlorophyll and leaf area were evaluated. The density of two plants per hole, combined with larger spacings were the combinations that provided the highest liquid photosynthesis and chlorophyll values for the plants. The density of one plant per hole combined with 0.05 to 0.15 m spacings between plants were the ones that enabled higher crude photosynthesis and fresh mass of tubers values. The density of one plant per hole and 0.05 m spacing enabled higher mean productivity values and is the most suitable for radish cultivation.

Vegetable soybean: seed composition and production research

Vegetable soybean (edamame) [<em>Glycine max</em> (L.) Merr.] is a low input, high nutritional value, short crop cycle and soil-enriching profitable crop. It offers quick economic return and provides health benefits to the consumers. The market demand for edamame has begun to flourish and expand dramatically in recent decades due to increased awareness of nutritional properties, and the change in life styles towards healthier food. This article highlighted the importance of edamame as a nutraceutical and functional food-grade produce, summarised the research advances in seed composition and their roles, cultivar selection and crop establishment, planting date and fertilisation, weed management and harvesting. Current production problem of extensive labor at harvest and future research challenges in improving crop establishment, developing cultivars competitive to weed and resistant to pest insects/diseases, assessing biological activities of edamame elemental and phytochemical properties on cancer cell inhibition, and developing organic production system were also proposed with aims of enhancing farm profitability and expanding opportunities for extensive use of edamame.

Diagnosis of the Environmental and Economic Social Sustainability of the Faita Enclosure of the Canton Quevedo-Ecuador

The aim of this study was to perform the agroecological diagnosis to determine the sustainability of agricultural production system Campus Faita of Quevedo Canton province of Los Rios Ecuador applying the matrix of Battelle Columbus for the characterization of the physical, abiotic, socioeconomic environment and which also it served to extract sustainability indicators to assess production systems Campus. Faita is in the tropical dry forest area where the predominant plant cover crops are planted forests and grass where there is almost no native vegetation. The average farm area is 5 hectares, production is diversified with a pattern of prevalent crops such as cocoa, tropical fruit mostly associated, timber cultivation and short cycle crops corn and soybeans. The economy of farmers is critical, although the average income in the area is within the official indexes. There are ecological and pollution by burning action, noise problems (97%), deforestation (98%) and especially by the aerial spraying of banana close, prolonged drought in the summer. The pressure on land use is moderate, subsistence production systems account for 49%. Sustainability Assessment qualifies as sustainable when discussing environmental or production indicators, but social and economic development is not sustainable where systems generally are not sustainable as it achieves an overall average of 55, 52%.

Nitrogen×sulfur interaction on fertiliser-use efficiency in bread wheat genotypes from the Argentine Pampas

Wheat crop response to sulfur (S) depends on nitrogen (N) level, genotype and environmental conditions, demonstrating strong genotype × environment × nutrients interactions. The agronomic-use efficiency of both nutrients has not been evaluated in a wide range of modern genotypes differing in their cycle length and baking quality. The aim of this study was to analyse the effect of N and S fertilisation on yield components and use efficiency of both nutrients in 24 modern, high-yielding bread wheat genotypes (including long and short crop cycles) grown in contrasting environments in the Humid Pampa of Argentina. Two experiments were conducted under contrasting seasonal conditions on a Mollisol in Azul, Buenos Aires. Significant effects of N (range 15–200 kg N ha–1) on grain yield were observed in all genotypes. By contrast, responses to S (30–100 kg S ha–1) were found only at high N level in low soil-fertility environments, differing between long and short cycles. Genotype × fertilisation interaction was significant in the environment with higher soil fertility. Sulfur addition improved N-recovery efficiency (0.15 v. 0.32) and agronomic efficiency of the available N (84 v. 93 g g–1) in the poor-fertility environment, characterised by their N and S deficiency and moderate level of organic matter. Grain N-recovery efficiency was largely explained by increases in grain number, whereas S recovery was also associated with increases in grain nutrient concentration. We conclude that genotype and environment strongly alter fertiliser-use efficiency, providing valuable information for ranking genotypes and optimising site-specific management of wheat crops in the Humid Pampa of Argentina. Grain S percentage may be useful as a physiological marker for selection of bread wheat genotypes with high apparent S recovery.

Green manure-15N absorbed by broccoli and zucchini in sequential cropping

Short-cycle crops use part of the N from green manure fertilization, while the remainder continues to be available for the subsequent ones. The aim of the present work was to evaluate the N use efficiency of sunn hemp, Crotalaria juncea L. (Fabaceae) in the sequential cropping of Brassica oleracea var. italica (Brassicaceae) followed by zucchini, Cucurbita pepo L. (Cucurbitaceae). Three doses of C. juncea green manure 3, 6, and 9tha−1 were evaluated, each one added with 12tha−1 of organic compost. The N use efficiency was based on the 15N isotope dilution technique. The total N accumulated in the shoots of broccoli and zucchini with the highest dose of C. juncea was 78.25 and 70.42kgha−1, respectively. The green manure-N recovery efficiency and quantity with the highest doses of C. juncea in broccoli were 74.39 and 47.42kgha−1 and in zucchini 58.82 and 31.95kgha−1, respectively. The green manure-N supplied 28.50% of N for broccoli and 16.22% for zucchini. The N residual effect from C. juncea green manure is enough to provide for the cultivation of at least two vegetable crops — broccoli followed by zucchini.

Análisis Del Comportamiento De Las Precipitaciones En Quevedo - Ecuador, Para La Planificación De Cultivos

The work was performed with the aim of knowing the rainfall of the city of Quevedo in Ecuador, to improve the calendars of short-cycle crops, since this information is commonly required by farmers in the area and agricultural professionals who work as technical advisers. Processing a series of recordings of rainfall of 35 years belonging to the Pichilingue Weather Station of the National Institute of Meteorology and Hydrology located on the premises of the National Agricultural Research Institute, the methodology applied was focuses on the determination of statisticians as the average, Standard Deviation, Variance, coefficient of variation, skewness and kurtosis coefficient; then based on the average are determined wet and dry periods the frequency and the intensity with which they occur. That also was detected in this town from 1980 to 2014 there were 10 dry periods and nine wet periods, which are presented with a frequency of 3,8 and 3,6 years respectively. Based on the results, the wet season is defined between the months of December to May and the dry season from June to November. The foil available average rain accumulated determined for the wet and dry periods has the following values: 953,3 mm, 2924,2 mm and an average of 2216,3 mm. Short-cycle crops of the area should be planted since the month of December to be exploited all the rain of the wet season.

Amendoim (Arachis sp.) como fonte na matriz energética brasileira

Biodiesel is a renewable and sustainable fuel. In recent decades the growing demand for energy and environmental awareness generates great interest in obtaining alternative fuels from renewable resources, such as biodiesel. All highlighting the new fuel requires a thorough study of all the productive chain. Among the oil that stands out, the peanut is a promising alternative for obtaining biodiesel. In this sense this study conducted documentary research on the oil crop peanut ( Arachis sp.) Belonging to the biodiesel production chain, which is inserted in the National Agro-Energy Plan. Considering the vegetative, ecological and economic aspects of oilseed peanut regarding culture in the biodiesel production chain is of particular importance, due to be among the short cycle crops. However the economic viability becomes a standstill due to peculiarities involving the crop production system.

Parent plant vs sucker − how can competition for photoassimilate allocation and light acquisition be managed in new banana hybrids?

Dessert banana production worldwide is based on just a few highly productive, easy to grow and international market compatible cultivars from the Cavendish sub-group (AAA genome). However, these cultivars are hampered by pests and diseases, which has led to extensive pesticide use. New pest and disease resistant varieties that are productive enough to meet international market demand are now needed to reduce pesticide use and thus the detrimental environmental impact. Hybrid bananas bred by the CIRAD banana breeding program are resistant to many diseases, particularly Sigatoka diseases, but exhibit morphological traits and yield components which differ markedly from those of Cavendish bananas. After an analysis of traits related to plant morphology and yield in 530 banana hybrids, the effects of modifying the level of competition between bunches and suckers through sucker pruning management practices were compared on the new hybrid CIRAD 925 and on a reference variety from the Cavendish sub-group ‘Grande Naine’. Hybrids from the CIRAD banana breeding program tend to have thin stems, small bunches and a short crop cycle. Total sucker pruning until mother plant harvest significantly increased the fruit diameter, first cycle bunch weight, second cycle duration and decreased the plant size. However, the effect on bunch weight was greater for Grande Naine, while the effects on second cycle duration and pseudostem girth were greater for CIRAD 925. The level of apical dominance of the central meristem on suckers seemed to explain the varietal differences in the effects of sucker pruning management. Our results showed that traits related to plant morphology and yield components could be modified by sucker pruning management and that a tailored management of mother-plant/sucker competition could be a way to improve the suitability of new hybrids for the banana industry.

Evaluation of Cycloate Followed by Evening Two-Leaf–Stage Phenmedipham Application in Fresh Market Spinach

Fresh market spinach has one primary herbicide, cycloate, which does not control all weeds. Previous studies demonstrated that cycloate PRE followed by (fb) phenmedipham at the four-leaf spinach stage is a safe and effective treatment. However, this treatment is not useful for the main growing season of fresh spinach due to its short crop cycle and the 21-d preharvest interval requirement of phenmedipham. This study evaluates the potential to use the combination of cycloate PRE fb phenmedipham on two-leaf spinach. Greenhouse and field studies were conducted in 2014 using three spinach varieties with low (‘Nordic' and ‘Sardinia') and high (‘Regal') tolerance to phenmedipham. Greenhouse studies revealed that phenmedipham at 90 g ai ha−1was safe to Regal when applied at the two-leaf stage. Sardinia was more susceptible to phenmedipham injury under high (310 W m−2) light conditions than low (258 W m−2) light conditions. Impact of time of day on phenmedipham safety was evaluated in the field: day-long exposure to high light intensity following morning applications vs. evening applications fb exposure to low light intensity. Injury estimations taken 3 d after treatment (DAT) were lower for evening than for morning applications. Nonetheless, injury 11 DAT and spinach yield evaluations found no differences between morning and evening applications. Subsequently, cycloate (1,700 g ha−1) PRE fb phenmedipham (90 and 180 g ha−1) applied in the evening at the two-leaf stage was evaluated. A reference treatment was cycloate PRE fb phenmedipham (270 g ha−1) at the four-leaf stage. Treatments with cycloate fb two-leaf phenmedipham at 90 and 180 g ha−1were safe to spinach and improved weed control compared to cycloate alone. Cycloate fb 180 g ha−1phenmedipham at the two-leaf stage reduced weed biomass by 88% compared to cycloate alone. This level of weed control was similar to the reference treatment. Results here show that phenmedipham applied at the two-leaf stage is safe to fresh market spinach and it has the potential to be used during most of the fresh spinach growing season.