Effect of variety and location on the glycoalkaloid content of potatoes

Significant differences in tuber glycoalkaloid (TGA) content were found among five commercial varieties and B5141-6 grown at 39 different locations in 28 states. Line B5141-6 had the highest average TGA content, 29.3 mg/100 g in 1970 and 28.1 mg/100 g in 1971. Average TGA contents in 1970 of Kennebec, Russet Burbank, Katahdin, Irish Cobbler, and Red Pontiac were 9.7, 7.9, 7.9, 6.2, and 4.3 mg/100g, respectively. There were also significant location effects. Possible causes of high TGA levels are discussed.     

The effect of systemic pesticides on total glycoalkaloid content of potato tubers at harvest

Two studies were conducted to determine the effect of systemic pesticides on the potato tuber total glycoalkaloid (TGA) content at harvest. In a field study, a pretuberization application of three systemic insecticides (disulfoton, aldicarb, carbofuran) and three systemic fungicides (thiabendazole, benomyl, thiophanate methyl) on three potato cultivars (Cobbler, Katahdin and B5141-6) showed carbofuran to be the only treatment significantly different (P= .05) from the control. The tuber TGA content of the carbofuran treatment was lower than that of the control. In a greenhouse study, carbofuran applied during tuberization to three potato varieties (Norland, Kennebec, Abnaki) produced a highly significant increase (P= .01) in the tuber TGA content. A significant varietal difference (P=.01) in response to the carbofuran treatment was also evidenced.     

Glycoalkaloids in potato tubers grown under controlled environments

Tuber content of α-solanine, α-chaconine, and total glycoalkaloids (TGA) was determined for the potato cultivars, Norland, Russet Burbank, and Denali grown under different environmental conditions in growth chambers. The lowest TGA concentrations (0.30 to 0.35 mg g¹ dry tissue) were found in the cv. Norland with 400 μnol m^-2 s^-1 photosynthetic photon flux (PPF), 12 h day length, 16 C temperature, and 350 μmol mol^-1 carbon dioxide. The ratio of α-chaconine to α-solanine was close to 60:40 under all growing conditions, except that it was 50:50 under the low temperature of 12 C. Cultivars responded similarly to environmental conditions although TGA was about 20% greater in cv. Russet Burbank and about 30% greater in Denali compared to Norland. The largest changes in TGA occurred with changes in temperature. In comparison to 16 C, TGA were 40% greater at 12 C, 80% greater at 20 C, and 125% greater at 24 C (0.70 mgg ^-1 dry weight). The TGA concentratation increased from 10 to 25% with an increase in light from 400 to 800 μmol m^-2 s^-1 PPF for all three cultivars. TGA increased 20% with extension of the day length from 12 to 24 hr and also increased 20% when carbon dioxide was increased from 350 to 1000 umol mol^-1. TGA concentrations were not influenced by changes in relative humidity from 50 to 80%. TGA concentrations decreased only slightly in harvests made from 9 to 21 weeks after planting. Variations in TGA among the different growing conditions and cultivars were below 20 mg/100 g fresh weight (= 1.0 mg g^-1 dry weight) recognized as the upper concentration for food safety. However the results suggest that TGA should be considered when potatoes are grown at temperatures above 20 C.     

评价适合选育加工型马铃薯品种的杂交组合

中国马铃薯的种植面积和产量均占世界首位,随着人们生活水平的提高和饮食结构的改善,以及外资企业在中国的纷纷建厂,对食品加工型马铃薯品种的市场需求日益增加,食品加工型马铃薯品种的培育已成为当务之急。本文根据食品加工型马铃薯品种的6项选育指标(炸制品质、薯形、产量、大中薯率、抗病性、熟期),对14个马铃薯杂交组合进行单个指标的评价和组合的级别评价,最终确定组合F81109×B5141-6、B5141-6×F58050、F67128×F61101、F49013×F61101、F71002×F59103可作为选育食品加工型马铃薯品种比较有前景的杂交组合。     

Effects of Different Nitrogen Fertilizer Levels and Native Soil Properties on Rice Grain Fe, Zn and Protein Contents

Deposition of protein and metal ions (Fe, Zn) in rice grains is a complex polygenic trait showing considerable environmental effect. To analyze the effect of nitrogen application levels and native soil properties on rice grain protein, iron (Fe) and zinc (Zn) contents, 32 rice genotypes were grown at three different locations each under 80 and 120 kg/hm2 nitrogen fertilizer applications. In treatments with nitrogen fertilizer application, the brown rice grain protein content (GPC) increased significantly (1.1% to 7.0%) under higher nitrogen fertilizer application (120 kg/hm2) whereas grain Fe/Zn contents showed non-significant effect of nitrogen application level, thus suggesting that the rate of uptake and translocation of macro-elements does not influence the uptake and translocation of micro-elements. The pH, organic matter content and inherent Fe/Zn levels of native soil showed significant effects on grain Fe and Zn contents of all the rice genotypes. Grain Zn content of almost all the tested rice genotypes was found to increase at Location III having loamy soil texture, neutral pH value (pH 6.83) and higher organic matter content than the other two locations (Locations I and II), indicating significant influence of native soil properties on brown rice grain Zn content while grain Fe content showed significant genotype × environment interaction effect. Genotypic difference was found to be the most significant factor to affect grain Fe/Zn contents in all the tested rice genotypes, indicating that although native soil properties influence phyto-availability of micronutrients and consequently influencing absorption, translocation and grain deposition of Fe/Zn ions, yet genetic makeup of a plant determines its response to varied soil conditions and other external factors. Two indica rice genotypes R-RF-31 (27.62 μg/g grain Zn content and 7.80% GPC) and R1033-968-2-1 (30.05 μg/g grain Zn content and 8.47% GPC) were identified as high grain Zn and moderate GPC rice genotypes. These results indicate that soil property and organic matter content increase the availability of Fe and Zn in rhizosphere, which in turn enhances the uptake, translocation and redistribution of Fe/Zn into rice grains.     

Colourimetric and fluorimetric substrates for the assay of limit dextrinase

The measurement of limit-dextrinase (LD) (EC 3.2.1.142) in grain samples such as barley, wheat or rice can be problematic for a number of reasons. The intrinsic LD activity in these samples is extremely low and they often contain a limit-dextrinase inhibitor and/or high levels of reducing sugars. LD also exhibits transglycosylation activity that can complicate the measurement of its hydrolytic activity. A minor modification to the industrial standard Limit-Dextrizyme tablet test is suggested here to overcome this transglycosylation issue.In addition, two new substrates are described that can be adopted for use in an auto-analyser format. 4,6-O-benzylidene-2-chloro-4-nitrophenyl-β-6³-α-d-maltotriosyl-maltotrioside (BzCNPG₃G₃, Hexachrom) is not susceptible to transglycosylation and serves amiably as a routine quantitative assay tool with the potential to run kinetic assays due to the low pK_a (∼5.5) of the chromogenic moiety while 4,6-O-benzylidene-4-methylumbelliferyl-β-6³-α-d-maltotriosyl-maltotrioside (BzMUG₃G₃, Hexafluor) was found to be susceptible to transglycosylation with LD. It is anticipated that Hexafluor may find extensive use in applications where high sensitivity is required such as high throughput screening studies.     

Performance of diverse upland rice cultivars in low and high soil fertility conditions in West Africa

Traditional tropical japonica (Oryza sativa) and Oryza glaberrima cultivars are typically grown in low-input, subsistence production systems in the uplands of West Africa by resource-poor farmers. In these systems, low soil fertility (LF), which is generally associated with lower organic carbon content, and N and P availability, is one of the major constraints to rice productivity. Thus, cultivars adapted to LF are needed for the food security of farmers, who would otherwise be solely reliant on nutrient inputs to increase productivity. This study evaluated the performance of six diverse cultivars grown in LF and high soil fertility (HF) conditions with supplemental irrigation over two seasons. Average grain yield across all cultivars in LF was 54% of that in HF (156 vs. 340 g m⁻²). Three improved indica rice cultivars and CG 14 (O. glaberrima) out-yielded Morobérékan (traditional tropical japonica) and WAB450-IBP-38-HB (progeny from interspecific hybridization of tropical japonica and O. glaberrima) in LF (181 vs. 105 g m⁻² on average). The high grain yield in LF was the result of large spikelet number m⁻² due to superior tillering ability and high harvest index rather than biomass production. The high-yielding cultivars in LF consistently had lower leaf chlorophyll content and higher specific leaf area during the period from the early vegetative stage through the reproductive stage. Among them, two indica cultivars (B6144F-MR-6-0-0 and IR 55423-01) were also high yielding in HF. The use of improved indica cultivars adapted to LF, but also with input-responsiveness, appears to offer an attractive and economical approach to improving upland rice productivity and widening genetic diversity in this region.     

Inheritance of resistance toFusarium sulphureum in crosses betweenS. tuberosum potato cultivars measured on field and glasshouse grown tubers

Summary Solanum tuberosum potato cultivars with differing levels of resistance to dry rot caused byFusarium sulphureum were hybridised in a half diallel crossing programme. Glasshouse grown tubers from true seedlings and field-grown tubers of the resulting progenies were assessed for their resistance toF. sulphureum. Statistical analysis revealed differences between the progenies forF. sulphureum resistance on both field and glasshouse grown tubers. On the field grown tubers, differences between progenies were due to differences in the general combining ability (GCA) of the parents. Parental phenotypes and GCA values were highly correlated. Overall. GCA was consistent for resistance or susceptibility, and glasshouse grown progenies showed a good correlation for GCA between years (r=0.85^***), and with the results of the field grown progenies (r=0.61^* in 1998 and r=0.69^** in 1999). It appears that resistance toF. sulphureum is heritable, and that this heritability is better assessed on field grown rather than glasshouse grown tubers, although the two are largely in agreement.     

Effects of genotype and environment on avenanthramides and antioxidant activity of oats grown in northwestern China

To investigate the effects of genotype and growing environment on avenanthramides and antioxidant activity of oats, the total phenolic content (TPC), avenanthramide compositions, and antioxidant activity were determined for whole oat from 39 cultivars grown in four locations in northwestern China (Inner Mongolia, Qinghai, Shanxi and Gansu). The results demonstrated that environment (E), genotype (G) and the interaction of these factors (E × G) significantly affected TPC, concentration of avenanthramide 2c (2c, ranged from 6.24 to 136.20 mg kg⁻¹), avenanthramide 2p (2p, 6.07–112.25 mg kg⁻¹), avenanthramide 2f (2f, 7.26–222.77 mg kg⁻¹) and antioxidant activity of oats. The effect of E was considerably greater than that of G or E × G. Based on G plus G × E interaction biplots (GGE biplots) analysis, the four locations in northwestern China can be divided into either two or three regions. Qinghai was determined to be distinct from the other locations. Cultivar Bayou 9 and oats grown in Gansu exhibited the highest TPCs, concentrations of 2c, 2p, 2f and antioxidant activity. The results suggest that oats containing more avenanthramides and exhibiting high levels of antioxidant activity could be obtained by selecting an appropriate genotype and growth location.     

Populations of aphids on named varieties of Irish potatoes

Populations of the green peach aphid,Myzus persicae (Sulzer), and the potato aphid,Macrosiphum euphorbiae (Thomas), were observed on 27 named varieties of Irish potatoes in the Yakima Valley of Washington intermittently from 1947 through 1968. The Epicure, Great Scot, and B5141-6 varieties produced relatively fewer green peach aphids than other varieties tested; Bliss Triumph and Red Pontiac produced relatively fewer potato aphids. Except for Doebay Red, the red-skinned varieties, Bliss Triumph, Red McLure, Norland, and Earnly Rose, were extremely to moderately productive of the green peach aphid. No correlation was apparent between abundance of aphids and the specific gravity or yield of tubers.     

NMR-Based Metabolomic Analysis of Spatial Variation in Soft Corals

Soft corals are common marine organisms that inhabit tropical and subtropical oceans. They are shown to be rich source of secondary metabolites with biological activities. In this work, soft corals from two geographical locations were investigated using ¹H-NMR spectroscopy coupled with multivariate statistical analysis at the metabolic level. A partial least-squares discriminant analysis showed clear separation among extracts of soft corals grown in Sanya Bay and Weizhou Island. The specific markers that contributed to discrimination between soft corals in two origins belonged to terpenes, sterols and N-containing compounds. The satisfied precision of classification obtained indicates this approach using combined ¹H-NMR and chemometrics is effective to discriminate soft corals collected in different geographical locations. The results revealed that metabolites of soft corals evidently depended on living environmental condition, which would provide valuable information for further relevant coastal marine environment evaluation.     

Weed emergence as affected by maize (Zea mays L.)-cover crop rotations in contrasting arable soils of Zimbabwe under conservation agriculture

Weed control in smallholder farming systems of sub-Saharan Africa is labour intensive or costly. Many researchers have therefore advocated for the use of cover crops in weed management as an affordable alternative for smallholders. Cover crops may be grown in rotations to suppress weeds and reduce the reliance on herbicides. The use of cover crops creates microenvironments that are either conducive or inhibitive to the emergence of certain weed species. A study, initiated in 2008 in contrasting soils at four different locations of Zimbabwe, investigated the effect of maize (Zea mays L.)-cover crop rotations on the emergence of weeds that showed dominance in those soils. Weed assessments were however, carried out from 2011 to 2014. The weed species Galinsoga parviflora Cav., Commelina benghalensis L., and Richardia scabra L. showed dominance in all four locations with weed densities as high as 500 plants m⁻² being recorded for R. scabra L. in a sandy soil. Maize-cover crop rotations resulted in higher densities of Bidens pilosa compared with maize monocropping (control treatment) due to its high nitrogen (N) requirement to produce more seeds. On the other hand, the integration of cover crops such as pigeon pea [Cajanus cajan (L.) Millsp.] that had poor shading qualities, due to large gaps or spaces and slower initial growth, had limited effects on competitive weeds such as Cyperus esculentus L. which tend to dominate exhausted soils. The density of C. esculentus was 38% greater in maize–pigeon pea rotations compared with the control treatment. Variability between seasons and sites affected emergence of all weeds in the present study, which masked long-term trends. The results suggest that there is need to identify the germination and emergence requirements of specific weeds and select cover crops best suitable for their control. The study provides useful information for farmers and advisors on the best cover crops for control of certain problematic weeds in different soil types of Zimbabwe.     

SSR-based and grain yield-based diversity of hybrid maize in Thailand

Commercial hybrid maize varieties are often used to extract new inbred lines in hybrid breeding programs. Seven commercial hybrid maize varieties were crossed in a diallel design, and the resulting hybrids and selfed progeny were evaluated for yield and adaptability grown in six locations in Thailand. The parental varieties were analyzed with a set of 64 Simple Sequence Repeat (SSR) loci, spanning all 10 chromosomes. The average number of alleles per SSR locus was 4.98 with a range of 2–11. The polymorphic information content (PIC) varied from 0.24 to 0.89, with an average of 0.69. Using SSR-based genetic distance (GD), an UPGMA dendrogram showed seven field corn varieties classified into three distinct groups. Troyer's genetic distance (TGD) calculated from yield data, which is a function of inbreeding depression, varied from 0.493 to 1.015 between different parental combinations. A significant positive correlation was found between the GD and TGD across the six locations (0.66^**). The GD correlated positively with specific combining ability (SCA) as well across all locations (r = 0.76^**) heterosis was significant for grain yield and SCA, accounting for 47% of the sum of the square among entries. Therefore, we suggest that broad base populations derived from each of the distinct groups can be formed using combined criteria of SSR-based GD, TGD, grain yield, GCA and SCA.     

The effect of light intensity on Colorado potato beetle resistance and foliar glycoalkaloid concentration of fourSolanum chacoense clones

Controlled environment experiments were used to determine the effect of light intensity on levels of glycoalkaloids and resistance to the Colorado potato beetle (CPB),Leptinotarsa decemlineata Say, inSolanum chacoense Bitter clones that synthesized acetylated glycoalkaloids, the leptines. Plants were grown under two light intensities, 50 or 250 ?mol m^-2S^-1, and bioassayed for CPB resistance by placing neonate larvae on excised foliage. Larval development stage and mortality were recorded after four days. The leptine-synthesizing clones responded to the increase in light intensity with a 2–4 fold increase in level of foliar leptines. Larval development rate on foliage from plants grown under high light intensity was reduced and larval mortality increased. Results showed a significant (p>0.05) effect of light on glycoalkaloid synthesis and CPB resistance.     

Foliar resistance to late blight in potato clones evaluated in national trials in 1997

Changes in the oomycetePhytophthora infestans in the United States and other parts of the world pose a significant threat to potato production. A continual evaluation of potato clones for resistance to late blight is necessary to identify clones with resistance and to monitor the stability of resistance in light of the emergence of new and more aggressive strains of this pathogen. Twentytwo potato clones (10 cultivars and 12 selections) were evaluated in 1997 for late blight resistance at seven U.S. locations. Seven late blight differentials (R₁R₂R₃R₄, R₁R₂R₄, R₁R₃R₄ R₃, R₈ R₁₀, and R_multi) were also included in the test at five of these locations. The US-8 strain of P.infestans was present at all locations. Percent infected foliage was recorded at approximately weekly intervals following the onset of disease. Area under the disease progress curve (AUDPC) was calculated. The nonparametric stability statistics mean absolute rank differences (S _i ⁽¹⁾ ) and variances of the ranks (S _i ⁽²⁾ ) were used to analyze phenotypic stability. Although neither of these statistics was significant for individual clones, both of these statistics were significant when summed over clones, indicating the importance of genotype × environment interactions on the rankings of these clones across locations. The most late blight-resistant and susceptible clones were the most stable; clones in the intermediate ranges were most subject to rank changes due to genotype × environment interactions. The most late blight-resistant clones were AWN86514-2, B0692-4, B0718-3, and B0767-2. The most susceptible clones were B0811-13, B1004-8, Nor-Donna, and Krantz. AUDPC was very low for the late blight differentials R₈ and R_multi, moderately low for R₁₀ and very high for the remaining differentials. This study is important in characterizing the reaction of potato clones to new strains of P.infestans.     

Partitioning of photoassimilates by potato plants (Solanum tuberosum l.) as influenced by irradiance: II. Partitioning patterns by four clones grown under high and low irradiance1

This paper is the second in a three-part series describing the influence of varied irradiance on growth and photoassimilate partitioning by potato plants. Four clones (Russet Burbank, Lemhi Russet, A66107-51, and A6948-4) were grown under two light regimes: a) high light levels (HL) of 500 to 1200 μE m^-2 s^-1, varying with changes in natural sunlight and time of day, and b) low light levels (LL) at approximately one quarter of high light (21 to 28%). Three weeks after tuber initiation, the most recently-matured leaf was labelled with¹⁴CO₂, and plants were harvested: 1) one day after labelling, and 2) two weeks after labelling. Plants of all clones responded to the low light levels in a similar way by: 1) changing some morphological characteristics, 2) decreasing biomass accumulation and tuber yield, and 3) changing the sink-source relationship by promoting growth of leaves and stems at the expense of tubers. However, there were evident clonal differences in reactions to growth under low light; e.g., Lemhi Russet appeared to be most sensitive to light stress, while clones A66107-51 and A6848-4 were much less sensitive. No matter what the prior light history (HL or LL), clone A6948-4 was able to maintain higher rates of photosynthesis than the other clones at all light levels between 200 and 1200 μE m^-2 s^-1. This study showed that the potential exists to breed for cuttivars that can maintain higher rates of photosynthesis and higher tuber yield under low light levels.     

High Yielding Performance of Soybean in Northern Xinjiang,China

Abstract

The experimental site (Shihezi, Xinjiang, China) is located in an arid area of central Asia with abundant solar radiation of almost 10 daily sunshine hours from April to September. The yield potential in this area appears to be high if sufficient water is supplied. The yields of five soybean (Glycine max (L.) Merr.) cultivars including three semi-indeterminate Chinese cultivars (Shidadou 1, Xindadou 1 and Suinong 11) and two determinate Japanese cultivars (Toyomusume and Toyokomachi) were evaluated over three years. These cultivars were grown under drip irrigation, a high planting density (22.2 plants m^-2) and heavy applications of farmyard manure (15 t ha^-1). Each cultivar showed a high leaf area index (LAI). In particular, the maximum LAI was greater than 7 over the three years in Shidadou 1 and Toyokomachi. The three Chinese cultivars with a high plant height had a low LAI in the upper layers of the canopy, but the two Japanese cultivars with a short plant height had a higher LAI in the middle or upper layers. Toyokomachi and Shidadou 1 had the highest seed yield, followed by Toyomusume. In particular, the seed yield of Toyokomachi was as high as 8.67 t ha^-1 on the average of the three years. These high-yielding cultivars had more than 60 pods per plant (1350 m^-2). The high yields in this experiment could be due to the large amount of intercepted radiation owing to the high LAI and abundant solar radiation, frequent and sufficient irrigation by the drip irrigation, and large number of pods as a sink.     

Occurrence of Viruses Affecting Potato Crops in Khartoum State-Sudan

The incidence of Alfalfa mosaic virus (AMV), Potato leafroll virus (PLRV), and Potato virus Y (PVY) in potato crops derived from various types of seed potatoes was assessed visually and confirmed by direct tissue blot immunoassay, over two winter growing seasons (1999/2000, 2000/2001) at three locations, Elnaiya, Elshehinab, and Shambat in Khartoum State, the main potato growing region in Sudan. Virus infection was most prevalent in 2000/2001. In general, crops grown directly from imported certified seed potatoes and from “improved seed”, produced in Sudan from imported basic seed, showed the lowest levels of PLRV and PVY compared with crops grown from Sudanese farm saved seed. For AMV, however, only crops grown directly from imported certified seed potatoes had low levels of AMV. Crop location also affected virus incidence, although this varied with year. For AMV, levels were similar at all locations in 1999/2000, but were greatest at Elnaiya in 2000/2001. For PVY, levels were greatest at Elnaiya in 1999/2000 and Shambat in 2000/2001. For PLRV, no symptoms were observed in 1999/2000 and virus levels were similar for all locations in 2000/2001. This study reports for the first time the occurrence of AMV in potatoes grown in Sudan.     

Yield Stability of Aromatic Upland Rice with High Yielding Ability in Indonesia

Abstract

Aromatic rice variety, Mentikwangi, was crossed with high-yielding upland rice variety, Poso, and the pedigree was selected to obtain lines with high yielding and aromatic characters. The objectives of the research were to study the yield stability of aromatic upland genotypes across different locations and to select aromatic upland rice genotypes having wide adaptability, and or specific location adaptability. Yield stability of genotypes was estimated by using regression lines proposed by Finlay and Wilkinson. Some genotypes showed high yield stability and wide adaptability in different locations, and others showed good adaptability to a specific location. The lines having high yield stability and wide adaptability were G10 (405 g m-²), G19 (400 g m-²), G39 (418 g m-²), and G136 (411 g m-²), which may be considered as candidates of new aromatic upland rice cultivars. Situpatenggang had specific adaptability at the fertile locations; and Poso and G13 at the infertile locations. Genotype x location interactions for the yield and its components performance were observed.     

The degree of starch phosphorylation as influenced by phosphate deprivation of potato (Solanum tuberosum L.) plants

Summary The levels of starch phosphorylation in potato tubers were investigated in relation to fertilization with phosphorus (P) of field-grown and greenhouse-grown plants. The field-grown plants received 0, 15 or 30 kg P ha⁻¹. Starch from plants grown without P-fertilizer contained 15.6 nmol P (mg starch)⁻¹ whereas starch from plants grown with 30 kg P ha⁻¹ contained 20.6 nmol P (mg starch)⁻¹. The greenhouse-grown plants were cultured in inert media and received nutrient solutions containing 0, 3, 12 or 24 mg P l⁻¹, respectively. Plants grown with no P-fertilizer produced tuber starch with phosphorylation levels reduced to approximately 30% of the level found in plants grown with an ample supply of P. Thus, the level of starch phosphorylation can be modified by limiting the P-supply through the root system. Application of foliar P-fertilizer to the greenhouse-grown plants had no significant effect on the phosphorylation of the tuber starch.