Storage Root Yield Research Articles

Sweetpotato cultivars responses to interactive effects of warming, drought, and elevated carbon dioxide.

Plants are sensitive to changes projected in climates, such as elevated carbon dioxide (eCO2), high temperature (T), and drought stress (DS), which affect crop growth, development, and yield. These stresses, either alone or in combination, affect all aspects of sweetpotato plant growth and development, including storage root development and yield. We tested three sweetpotato cultivars (Beauregard, Hatteras, and LA1188) responses to eight treatments (Control, DS, T, eCO2, DS + T, T + eCO2, DS + eCO2, DS + T + eCO2). All treatments were imposed 36days after transplanting (DAP) and continued for 47days. Treatments substantially affected gas exchange, photosynthetic pigments, growth, and storage root components. Cultivars differed considerably for many of the measured parameters. The most significant negative impact of DS was recorded for the shoot and root weights. The combination of DS + T had a significant negative effect on storage root parameters. eCO2 alleviated some of the damaging effects of DS and high T in sweetpotato. For instance, eCO2 alone or combined with DS increased the storage root weights by 22% or 42% across all three cultivars, respectively. Based on the stress response index, cultivar "Hatteras" was most tolerant to individual and interactive stresses, and "LA 1188" was sensitive. Our findings suggest that eCO2 negates the negative impact of T or DS on the growth and yield of sweetpotato. We identified a set of individual and interactive stress-tolerant traits that can help select stress cultivars or breed new lines for future environments.

A sustainable approach for weed and insect management in sweetpotato: breeding for weed and insect tolerant/resistant clones

AbstractWeed management is consistently ranked among the top priorities of the United States sweetpotato industry. To provide additional weed and insect management strategies for sweetpotato, we initiated development of insect-resistant germplasm that also has weed tolerance by breeding and selecting for sweetpotato clones that are fast growing and have semi-erect to erect canopy architecture. Field studies were conducted in 2018 and 2019 in Charleston, South Carolina, to quantify the effects of weed-free interval and sweetpotato clone on weed counts for naturally occurring weed species, storage root yield, and insect resistance to the major pests of sweetpotato. Weed-free intervals included plots that were weedy all season and weed-free for 2, 3, and 4 wk after transplanting. Sweetpotato clones evaluated included ‘Beauregard’, ‘Covington’, ‘Monaco’, and six advanced selections with semi-erect to erect plant habit. Significant weed-free interval and sweetpotato clone main effects were observed for all variables measured, but not for their interaction. Two sweetpotato clones, USDA-17-037 and USDA-17-077, were consistent across both years and had the lowest weed counts, exhibited enhanced insect resistance, and were the highest yielding entries. These results demonstrate the potential for development of insect-resistant sweetpotato germplasm with a vigorous, erect plant habit that may be less susceptible to weed interference than cultivars with spreading shoot growth. The combination of germplasm that is both resistant to insect pests and competitive with weeds can provide organic and subsistence sweetpotato growers solutions to these critical issues related to sweetpotato production.

Genetic Structure and Diversity Study of Cassava (<i>Manihot esculenta</i>) Germplasm for African Cassava Mosaic Disease and Fresh Storage Root Yield

A better understanding of population structure and genetic diversity among cassava germplasm for African cassava mosaic disease and fresh root yield traits is useful for cassava improvement programme. Phenotype-based selection for these traits is cumbersome due to phenotypic plasticity and difficulty in screening of phenotypic-induced variations. This study assessed quantitative trait loci (QTL) regions associated with African cassava mosaic disease (ACMD) and fresh storage root yield (FSRY) in 131 cassava (Manihot esculenta) genotypes using a genome-wide association study (GWAS). The single nucleotide polymorphism (SNP) loci and associated candidate genes, when validated, would be a valuable resource for marker-assisted selection in the breeding process for development of new cassava genotypes with improved resistance to ACMD and desirable high root yield. Population structure analysis using 12,500 SNPs differentiated the 131 genotypes into five distinct sub-groups (K = 5). Marker-trait association (MTA) analysis using the generalized linear model identified two QTL regions significant for ACMD and three for FSRY. This study demonstrated that DArTseq markers are useful genomic resources for genome-wide association studies of ACMD and FSRY traits in cassava for the acceleration of varietal development and release.

No-tillage and previous maize–palisadegrass intercropping reduce soil and water losses without decreasing root yield and quality of cassava

No-tillage (NT) is an alternative technique adopted in cassava (Manihot esculenta Crantz) growing areas to reduce soil loss. However, it may affect the development of storage roots depending on the soil-covering residues. This study evaluated the soil and water losses and storage root yield and quality of cassava planted in the dry and rainy seasons using conventional tillage (CT) and NT, following sole maize (Zea mays L.) cropping or maize–palisadegrass [Urochloa brizantha (Hochst. ex A. Rich.) R.D. Webster] intercropping. The experimental design was a randomized block with five replications. Four treatments were considered representing cassava planted using CT and NT following sole maize or maize–palisadegrass intercropping. CT caused soil loss of up to 43.4 Mg ha−1 over the 16 months of cassava cultivation. NT following maize–palisadegrass intercropping did not decrease cassava yield nor its quality and reduced both soil and water losses. In the rainy planting season, NT reduced soil loss by up to 80% (35 Mg ha−1), while in the dry planting season, the reduction varied between 28% and 38% (8–11 Mg ha−1). These findings suggest that previous maize–palisadegrass intercropping followed by NT of cassava is recommended for increasing soil conservation, especially in cassava planted in the rainy season.

Early-Stage Phenotyping of Sweet Potato Virus Disease Caused by Sweet Potato Chlorotic Stunt Virus and Sweet Potato Virus C to Support Breeding.

Sweet potato virus disease (SPVD) is a global constraint to sweetpotato (Ipomoea batatas) production, especially under intensive cultivation in the humid tropics such as East Africa. The objectives of this study were to develop a precision SPVD phenotyping protocol, to find new SPVD-resistant genotypes, and to standardize the first stages of screening for SPVD resistance. The first part of the protocol was based on enzyme-linked immunosorbent assay results for sweet potato chlorotic stunt virus (SPCSV) and sweet potato virus C (SPVC) with adjustments to a negative control (uninfected clone Tanzania) and was performed on a prebreeding population (VZ08) comprising 455 clones and 27 check clones graft inoculated under screenhouse conditions. The second part included field studies with 52 selected clones for SPCSV resistance from VZ08 and 8 checks. In screenhouse conditions, the resistant and susceptible check clones performed as expected; 63 clones from VZ08 exhibited lower relative absorbance values for SPCSV and SPVC than inoculated check Tanzania. Field experiments confirmed SPVD resistance of several clones selected by relative absorbance values (nine resistant clones in two locations; that is, 17.3% of the screenhouse selection), supporting the reliability of our method for SPVD-resistance selection. Two clones were promising, exhibiting high storage root yields of 28.7 to 34.9 t ha-1 and SPVD resistance, based on the proposed selection procedure. This modified serological analysis for SPVD-resistance phenotyping might lead to more efficient development of resistant varieties by reducing costs and time at early stages, and provide solid data for marker-assisted selection with a quantitative tool for classifying resistance.[Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.

Changes in sucrose metabolism patterns affect the early maturation of Cassava sexual tetraploid roots

Cassava (Manihot esculenta Crantz) is an important multiuse crop grown for economic and energy purposes. Its vegetative organs are storage roots, in which the main storage material is starch. The accumulation characteristics of starch in cassava roots can directly affect the yield, starch content and maturation of cassava storage roots. In this study, we used a cassava sexual tetraploid (ST), which showed early maturation heterosis in previous work, as the main test material. We analyzed the sucrose metabolism and starch accumulation characteristics of the ST and its parents from the leaf "source" to the storage root "sink" during different developmental stages and explored the regulatory mechanisms of ST storage root early maturation by combining the transcriptome data of the storage roots during the expansion period. The results showed that the trends in sucrose, glucose and fructose contents in the ST leaves were similar to those of the two parents during different stages of development, but the trends in the ST storage roots were significantly different from those of their parents, which showed high sucrose utilization rates during the early stage of development and decreased utilization capacity in the late developmental stage. Transcriptome data showed that the genes that were expressed differentially between ST and its parents were mainly involved in the degradation and utilization of sucrose in the storage roots, and four key enzyme genes were significantly upregulated (Invertase MeNINV8/MeVINV3, Sucrose synthase MeSuSy2, Hexokinase MeHXK2), while the expressions of key enzyme genes involved in starch synthesis were not significantly different. The results revealed that the pattern of sucrose degradation and utilization in the cassava ST was different from that of its parents and promoted early maturation in its tuberous roots. Starch accumulation in the ST from sucrose mainly occurred during the early expansion stage of the storage roots, and the starch content during this period was higher than that of both parents, mainly due to the regulation of invertase and hexokinase activities during sucrose metabolism. This study provides a basis for further genetic improvements to cassava traits and for breeding varieties that mature early and are adapted well to provide starch supply requirements.

Construction of a high-density SSR genetic linkage map and identification of QTL for storage-root yield and dry-matter content in sweetpotato

Sweetpotato (Ipomoea batatas (L.) Lam.) is a widely grown food crop especially in developing countries. Increasing storage-root yield and dry-matter content has been the main breeding objective of the crop, and DNA marker-assisted breeding is needed for this purpose. In this study, using a mapping population of 500 F1 individuals from a cross between Xushu 18 (female) and Xu 781 (male), we constructed a high-density genetic linkage map of sweetpotato using 601 simple-sequence repeat (SSR) primer pairs. The Xushu 18 map contained 90 linkage groups with 5547 SSR markers and spanned 18,263.5 cM, and the Xu 781 map contained 90 linkage groups with 4599 SSR markers and spanned 18,043.7 cM, representing the highest genome coverage yet reported for sweetpotato. We identified 33 QTL for storage-root yield and 16 QTL for dry-matter content, explaining respectively 6.5%–47.5% and 3.2%–18.9% of variation. These results provide a foundation for fine-mapping and cloning of QTL and for marker-assisted breeding in sweetpotato.

Assessment of water stress effects on red beet under the Mediterranean conditions

Although there are numerous scientific data on the response of various plants to water stress, there are few studies on red beet in the literature, and non-specifically under the Mediterranean conditions. This study aimed to investigate the effects of water stress (WS) levels (control-WS0, low-WS20, medium-WS40, high-WS60, and extreme-WS80) on water use, growth, yield parameters, and yield response factor of red beet (Beta vulgaris) in Mediterranean conditions. During the growing season, the highest daily evapotranspiration values were 3.7, 2.8, 2.1, 1.4, and 0.7 mm for the control treatment, low, medium, high, and extreme water stresses, respectively. Soil salinity, plant height, fresh leaf yield, and storage-root yield values were decreased as water stress increased. However, there were no significant differences in soil pH, taproot length, and plant water use efficiency between treatments. Significantly important strong- or moderate-positive linear correlations were observed between soil salinity, evapotranspiration, plant height, fresh leaf yield, and storage-root yield values. The yield response factors for red beet storage-root and fresh leaf yields were found to be 0.88 and 0.98, respectively. The results revealed that red beet is slightly tolerant to water stress, with comparatively lower storage-root and fresh leaf yield reductions under the reduced evapotranspiration caused by water stress.

Genotype by environment interaction effect on some selected traits of orange-fleshed sweet potato (Ipomoea batatas [L].Lam)

In Ethiopia, sweet potato is the 2nd and the most important root crop after Enset [Ensete ventricosum (Welw) Cheesman]. Even though widely cultivated in Ethiopia, the occurrences of wide agro-ecological variability are the key challenge for the selection of high yield and stable orange-fleshed sweet potato genotypes due the high interaction of genotype by environment effect (GEI). Until to date, the research reports on GEI and stability of orange-fleshed sweet potato genotypes under Southwest and West of Ethiopian conditions is very limited. Due to this fact, the study was conducted in main sweet potato growing of Southwest and West of Ethiopia since the 2019-2020 growing seasons. Nine Orange-fleshed sweet potato genotypes were evaluated in four different ecologies in completely randomized block design with three replications. The mainly indicative data and related variables were collected and analyzed by using ANOVA, AMMI, and GGE biplots. The ANOVA for total storage root yield revealed significant difference in the environments, genotypes, and the interactions of both (P < 0.001). The genotypes NASPOT-12 was the mostly performed one over all the rest with total fresh storage root yield of 55.88 ton ha-1 while Kulfo was performed as the lowest. The AMMI1 and AMMI2 biplot analysis revealed that, the genotypes NASPOT-12 was resulted in an above average mean of total fresh storage root yield and the genotype Koka-12, NASPOT-13, NASPOT-12, and Kulfo were far apart from the biplot origin which indicated the genotypes were the more responsive and largely contributed to the interaction component and thus considered as specifically adapted genotypes respectively. The GGE biplot revealed that the total variations of 79% with the PC1 accounted about 55% and the PC2 affect about 24% of variations approximately on the total fresh storage root yield of the tested orange-fleshed sweet potato genotypes. The "which won where" identified the three growing mega environments. In the comparison and ranking of the genotypes by the GGE biplot analyses, the genotype NASPOT-12 was more desirable than the rest genotypes. In the comparison and ranking of the environments by this analysis, the environment Jimma-1 was the most representative followed by Agaro-2 in the total fresh storage root yield of orange-fleshed sweet potato genotypes. Above all the genotype NASPOT-12 was responded well in most of the environments hence, recommended genotype for multipurpose advantage.

Effect of Leaf Harvest Intensity and Frequency on Sweet Potato Weevil (Cylas puncticollis) Infestation, Yield and Quality Traits of Sweet potatoes (Ipomoea batatas L.)

Objective: The present study assessed Cylas puncticollis (C. puncticollis) infestation, foliage, and root yields of sweet potatoes as influenced by the leaf harvest intensity and frequency in the inland valley swamp (IVS) and upland soils of Njala. Methods: The trial involved 2 varieties namely Kabia and Gbanie; 4 levels of foliage harvests: 0, 30, 60 and 90 days after planting; and 4 levels of leaf harvest intensities: 0, 25, 50 and 100%. The treatments were established in a randomized complete block design and replicated 3 times. The parameters that were investigated included the severity of C. puncticollis infestation on vines and storage roots, fresh foliage yield, storage root yields and other related traits (fresh storage root length, width and numbers). Results: Our findings showed that there were significant differences in foliage and root yields, as well as related traits among different leaf harvest frequency intensities. The 25 and 50% harvest plots produced optimum fresh foliage and storage root yields and other related traits of the crop. C. puncticollis infestation in sweet potatoes cultivated during the dry season in the IVS ecology was more severe than that in those grown in the upland during the wet season. The ecology and time of cultivation of sweet potatoes influence infestation by C. puncticollis on vines and roots more than the combined effects of putative varieties, leaf harvest intensity and frequency. Conclusion: Improved agronomic management practices support optimization of fresh leaf and root yields of sweet potatoes. These can be exploited and chosen to achieve optimum productivity and quality of the crop for both the fresh foliage and storage root consumers.

Evaluation of White fleshed sweet potato (Ipomoea batatas (L) Lam) Genotypes in different agro-ecologies of Southwest Ethiopia

A multi-locational evaluation trial of six white fleshed sweet potato genotypes was conducted in four locations during 2019 and 2020 cropping seasons. The objective of this study was to determine the magnitude of genotype by environment interaction (GEI) for storage root yield and yield-related traits of sweet potato genotypes and to assess the adaptability and stability of sweet potato genotypes in different production environments in southwest Ethiopia. Six genotypes were evaluated across eight diverse environments using a randomized complete block design (RCBD) with three replications. Data were collected on yield and yield components in all tested locations. The results showed highly significant difference (p&lt;0.01) for genotype effect, environmental affect and environment by genotype interaction (GEI) for all the traits studied. The analysis also revealed that the magnitude of the mean square of environment was higher than those of the genotype and GEI for all the traits studied indicating the uniqueness of the tested environments. The genotypes Hawassa-83, and Tula were identified both high mean root yield and high stability, closest to the ideal genotype for root performance and consistency of performance across environments. This study provides valuable information that could be utilized in a breeding program to ameliorate genotypes of sweet potato in Ethiopia.

Evaluation of released sweet potato [Ipomoea batatas (L.) Lam] varieties for yield and yield-related attributes in Semen-Bench district of Bench-Sheko-Zone, South-Western Ethiopia

Sweet potato is a significant root crop that can be used for both food and feed. Bench-Sheko zone mid-altitudes, in general, are among the most important sweet potato growing regions in southwest Ethiopia. During the 2017 and 2018 growing seasons, a study was carried out in the Semen-Bench district of the Bench-sheko zone, southwestern Ethiopia, to investigate the adaptability and performance of improved sweet potato varieties and to identify the best performer variety. A randomized complete block design with three replications was used to compare the performance of five improved (viz., Awassa-83, Beletch, Berkume, Kulfo, Tula) and one Local sweet potato variety. The results of both years and over year combined statistical analysis indicated that the varieties significantly varied in terms of all yield and yield-related traits. As a result, the Awassa-83 variety acquired the greatest values of average root diameter in both the 2017 (11.9 cm) and 2018 (10.1 cm) growing seasons, followed by the Berkume variety. In both 2017 and 2018 growing seasons and over year combined analysis, the highest average storage root length (21.5 cm), marketable storage root yield (29.06 ton/ha), total storage root yield (43.22 ton/ha), and storage root dry weight (42%) was recorded from variety Awassa-83. Variety Beletech and Berkume were found to be statistically similar and the next highest in terms of marketable storage root yield, and total storage root yield; moreover, variety Berkume was found to be the next highest in terms of storage root dry weight in two years combined result. On the other hand, the variety Beletech, which was closely followed by Awassa-83, had the highest average number of roots per plant (8.28) and the greatest number of marketable roots per plant (7.04). Therefore, considering overall traits Awassa-83 was found to be superior in overall performance and can be recommended for production in the study area and related agro-ecologies.

The Application of Nitrogen Source in Regulating Lignin Biosynthesis, Storage Root Development and Yield of Sweet Potato

The understanding of the effects of nitrogen sources on lignin synthesis in sweet potato during storage root formation is limited. In this study, we investigated the effects of different nitrogen source on sweet potato storage root formation and development, as well as lignin synthesis in potential storage roots. The sweet potato cultivars Shangshu 19 and Jixu 23 were used in field experiments in 2019 and 2020. Three treatments were tested: (a) no nitrogen fertilizer application (control); (b) 60 kg hm−2 ammonium nitrogen; and (c) 60 kg hm−2 amide nitrogen. The results indicate that during sweet potato storage root formation, ammonium nitrogen significantly enhanced root activity compared to that of the control. The ammonium nitrogen treatment promoted IbEXP1 and inhibited Ibkn1 and Ibkn2 expression during the early stages of storage root formation, then increased gibberellic acid and decreased zeatin riboside content, enhanced phenylalanine ammonia lyase and peroxidase activities, and promoted lignin synthesis in potential storage roots. The opposite effects of ammonium nitrogen treatment on gene expression, hormone contents, and enzyme activity were observed in the late stages of storage root formation. Relative to the control, the ammonium nitrogen treatment significantly increased the number of storage roots during canopy closure. The ammonium nitrogen treatment produced the highest storage root yield and number of storage roots per plant. These results indicated that the ammonium nitrogen can inhibit root lignin synthesis, then promote storage root formation and increase the yield of sweet potato.

Screening of some sweet potato (Ipomoea batatas (L.) Lam) genotypes for yield and damage by Cylas puncticollis under rainfed conditions in Umudike, Southeastern Nigeria

A field experiment was conducted at the National Root Crops Research Institute, Umudike, Southeastern Nigeria during the 2015 and 2016 cropping seasons to evaluate diversity among F1 population of sweet potato, namely: Sauti × 442162 (6), Ligri × Faara (17), Sauti × Bohye (17), including two checks (Umuspo 3 and TIS 87/0087). This experiment was laid out in a randomized complete block design with three replicates under rainfed condition. Data on fresh storage root yield were recorded at 120 days after planting. Analysis of variance, correlation and principal component analysis were utilized for data analysis. The study revealed that yield of fresh storage root showed significant differences (P&lt; 0.05) among the sweet potato genotypes. Sauti X Bohye produced the highest storage root yield (19.33 t/ha) in 2015 and performed better than the national check TIS 87/0087 that recorded a storage root yield of 10.84 t/ha. The result from the study showed that out of the forty genotypes evaluated, twenty-six (26) genotypes recorded attack of C. puncticollis. The extent of the damge recorded among the genotypes attacked by C. puncticollis ranged from severe damage to little damage among the genotypes that recorded fresh storage root damage. SautiXBohye/11, SautiXBohye/13, SautiXBohye/17 recorded severe damage caused by C. puncticollis while LigriXFaara/15 recorded moderate damaged caused by C. puncticollis. Fifteen (15) genotypes did not record any infestation by Cylas puncticollis. All characters except unmarketable storage root weight at harvest exhibited positive and significant (P&lt; 0.01) correlation with total roots weight (yield). Principal component analysis had three main principal components explaining 84.25% of the total variation with number of marketable roots, weight of marketable roots, storage root yield and Cylas incidence contributing the most to the first PCA. These genotypes could possess resistance genes to Cylas puncticollis and these genotypes could be incorporated in breeding programs for further trail.

Sweet Potato (Ipomoea batatas L.) Response to Incremental Application Rates of Potassium Fertilizer in Mississippi

Potassium (K) fertilization is a crucial component of sweet potato (Ipomoea batatas L.) production. The basis for K fertilizer recommendations in sweet potato production varies greatly and relies on studies conducted in the late 1950s–1970s. Changes in agronomic practices and increasing costs emphasize the need to revisit fertilizer recommendations. A field experiment was conducted to investigate the impact of seven different K fertilizer (K2O) application rates on sweet potato storage root yield, tissue K concentration, and economic implications in Mississippi. Incremental applications of K fertilizer did not influence sweet potato yield at any grade. Leaf tissue K concentration exhibited a quadratic trend in response to K fertilizer rate, with maximum leaf and root K content achieved at 269 and 404 kg·ha−1 K2O, respectively. Both the predicted K application rate for maximum yield and maximum profitability were the same, at 174 kg·ha−1 K2O. Accordingly, comparable sweet potato yields were achieved while applying substantially less fertilizer than the recommended rate. Further research is warranted to examine the impacts of only potassium fertilizer applications on soil characteristics and temporal trends in sweet potato potassium uptake, as well as refine fertilization recommendations for sweet potato production.

Combining ability and heritability analysis of sweetpotato weevil resistance, root yield, and dry matter content in sweetpotato

Efficient breeding and selection of superior genotypes requires a comprehensive understanding of the genetics of traits. This study was aimed at establishing the general combining ability (GCA), specific combining ability (SCA), and heritability of sweetpotato weevil (Cylas spp.) resistance, storage root yield, and dry matter content in a sweetpotato multi-parental breeding population. A population of 1,896 F1 clones obtained from an 8 × 8 North Carolina II design cross was evaluated with its parents in the field at two sweetpotato weevil hotspots in Uganda, using an augmented row-column design. Clone roots were further evaluated in three rounds of a no-choice feeding laboratory bioassay. Significant GCA effects for parents and SCA effects for families were observed for most traits and all variance components were highly significant (p ≤ 0.001). Narrow-sense heritability estimates for weevil severity, storage root yield, and dry matter content were 0.35, 0.36, and 0.45, respectively. Parental genotypes with superior GCA for weevil resistance included “Mugande,” NASPOT 5, “Dimbuka-bukulula,” and “Wagabolige.” On the other hand, families that displayed the highest levels of resistance to weevils included “Wagabolige” × NASPOT 10 O, NASPOT 5 × “Dimbuka-bukulula,” “Mugande” × “Dimbuka-bukulula,” and NASPOT 11 × NASPOT 7. The moderate levels of narrow-sense heritability observed for the traits, coupled with the significant GCA and SCA effects, suggest that there is potential for their improvement through conventional breeding via hybridization and progeny selection and advancement. Although selection for weevil resistance may, to some extent, be challenging for breeders, efforts could be boosted through applying genomics-assisted breeding. Superior parents and families identified through this study could be deployed in further research involving the genetic improvement of these traits.

COMPARACIÓN DE CLONES MEJORADOS DE CAMOTE (Ipomoea batatas [L.] Lam) EN EL RENDIMIENTO Y CONTENIDO DE BIOETANOL DE RAÍCES RESERVANTES

&lt;p&gt;&lt;strong&gt;Background:&lt;/strong&gt; Sweet potato (&lt;em&gt;Ipomoea batatas&lt;/em&gt; L.) is a crop of great importance in social, economic and industrial terms due to its forage aptitude, high yield potential and quality of storage roots, necessary as human food and also as raw material for bioethanol production a promising substitute for fossil fuels or to boost alcohol production. &lt;strong&gt;Objective:&lt;/strong&gt; To compare improved sweetpotato clones under different growing seasons and to select a promising new cultivar with high yield potential and bioethanol production from storage roots in Peru. &lt;strong&gt;Methodology:&lt;/strong&gt; The combined analysis of variance was used during two seasons (summer and spring) in Lambayeque, Peru. The yield of storage roots was evaluated, with respect to the quality, the percentage of dry matter and the production of bioethanol were evaluated, which was analyzed by the enzymatic hydrolysis of the starch of four clones and a control variety. &lt;strong&gt;Results:&lt;/strong&gt; The combined analysis of variance shows that the clones presented a significant effect on the variables under study. Likewise, the clone CIP 199071.8 with the highest yield of storage roots was identified during season 1 (summer) with an average of 67.4 ± 1.2 t ha&lt;sup&gt;-1 &lt;/sup&gt;and in season 2 (spring) with 73.4 ± 0, 8 t ha&lt;sup&gt;-1&lt;/sup&gt; regarding the combined analysis obtained 70.4 ± 1.1 t ha&lt;sup&gt;-1&lt;/sup&gt;. In addition, the present clone with an average of 28.9 ± 1.4% of dry matter stands out statistically, in fact the same clone 199071.8 reported the highest bioethanol production in season 1 (summer) with an average of 7089.6 ± 2, 2 L ha&lt;sup&gt;-1&lt;/sup&gt; of bioethanol and in season 2 (spring) it reached the highest bioethanol production with an average of 7875.1 ± 1.9 L ha&lt;sup&gt;-1&lt;/sup&gt;. Regarding the combined analysis, it obtained 7553.2 ± 1.7 L ha&lt;sup&gt;-1&lt;/sup&gt; of bioethanol.&lt;strong&gt; Implications:&lt;/strong&gt; The sweet potato clones had a significant effect on the yield and quality of the storage roots, a necessary source for human food or industrial input. &lt;strong&gt;Conclusion:&lt;/strong&gt; The clone CIP 199071.8 reached the highest yield of storage roots, dry matter and bioethanol production during the two growing seasons (summer 2019 and spring 2019), therefore, it will be released as a new cultivar.&lt;/p&gt;

Evaluation and Selection of Elite Cassava Varieties for Storage Root Yield in the Transition and Guinea Savannah Ecologies of Ghana

This study was carried out to identify and select local and improved cassava varieties suitable for cultivation in the transition and Guinea savannah agroecology of Ghana against climate change. Two agroecologies; transition and Guinea savannah ecologies were considered for the study. Four cassava growing communities were chosen in the transition zone whilst three cassava growing communities were chosen for the Guinea savannah ecology. The cassava varieties representing the treatments were arranged in a randomized complete block design with three replications at each location. A total of 13 cassava varieties were used for the study. Cassava cuttings measuring 20-25 cm were planted using a spacing of 1m × 1m. Harvesting was done at 12 months after planting to assess storage root yield of the cassava varieties at the different locations. Analysis of variance indicated significant (P≤ 0.05) varietal differences among the local varieties for root yield (11.25 - 29.27 t/ha), harvest index (0.46 – 0.75), storage root number per plant (2 - 8 roots/plant) and mean storage root weight (307.0 - 972.4 g) in Transition zone. However, there were no significant varietal differences between the improved varieties for root yield. The best performing improved varieties in the transition zone were Bankyehemaa (28.06 t/ha), Eskamaye (27.76 t/ha) and Nkabom (26.99 t/ha) whilst Filindiakong (22.65 t/ha) and Nyerikobga (31.17 t/ha) were identified to be suitable for the Guinea savannah ecology. Therefore, these cassava varieties can be cultivated to mitigate the effects of climate change on cassava and ensure food security.

Assessment of irrigation water salinity effects on red beet under Mediterranean conditions

Plant tolerance to salinity stress is vital for irrigation scheduling, decision-making, planning and operation, and most critically, water resource management. Although there are numerous scientific data on the response of various plants to salinity stress, there are few studies on red beet in the literature, and specifically under Mediterranean conditions. This study aimed to investigate the effects of water salinity stress on water use, growth, yield parameters, and salinity threshold and slope values of red beet in Mediterranean conditions. In addition to control (0.6 dS m-1), five irrigation water salinity levels including low (1.5 dS m-1), medium-low (3.0 dS m-1), medium (4.5 dS m-1), medium-high (6.0 dS m-1) and high salinity (8.0 dS m-1) stresses were used as treatments. Increased water salinities caused increases in electrical conductivity and pH values of saturated soil paste extracts and drainage waters, while decreases in water use affected plant height storage root yield and water use efficiency. The salinity threshold and slope values of red beet were determined as 3.10 dS m-1 and 4.42% per dS m-1.

Cassava-maize intercropping systems in southern Nigeria: Radiation use efficiency, soil moisture dynamics, and yields of component crops.

Efficient utilization of incident solar radiation and rainwater conservation in rain-fed smallholder cropping systems require the development and adoption of cropping systems with high resource use efficiency. Due to the popularity of cassava-maize intercropping and the food security and economic importance of both crops in Nigeria, we investigated options to improve interception of photosynthetically active radiation (IPAR), radiation use efficiency (RUE), soil moisture retention, and yields of cassava and maize in cassava-maize intercropping systems in 8 on-farm researcher-managed multi-location trials between 2017 and 2019 in different agro-ecologies of southern Nigeria. Treatments were a combination of (1) maize planting density (low density at 20,000 maize plants ha-1 versus high density at 40,000 maize plants ha-1, intercropped with 12,500 cassava plants ha-1); (2) fertilizer application and management targeting either the maize crop (90 kg N, 20 kg P and 37 kg K ha-1) or the cassava crop (75 kg N, 20 kg P and 90 kg K ha-1), compared with control without fertilizer application. Cassava and maize development parameters were highest in the maize fertilizer regime, resulting in the highest IPAR at high maize density. The combined intercrop biomass yield was highest at high maize density in the maize fertilizer regime. Without fertilizer application, RUE was highest at low maize density. However, the application of the maize fertilizer regime at high maize density resulted in the highest RUE, soil moisture content, and maize grain yield. Cassava storage root yield was higher in the cassava fertilizer regime than in the maize fertilizer regime. We conclude that improved IPAR, RUE, soil moisture retention, and grain yield on nutrient-limited soils of southern Nigeria, or in similar environments, can be achieved by intercropping 40,000 maize plants ha-1 with 12,500 cassava plants ha-1 and managing the system with the maize fertilizer regime. However, for higher cassava storage root yield, the system should be managed with the cassava fertilizer regime.