Asian Vegetable Research And Development Center Research Articles

“A bloodless social revolution”: Land reform and multiple cropping in Cold War Taiwan, 1950–1979

Societal Impact StatementMultiple cropping, the cultivation of several crops on the same land in a year, occupied an important part of Taiwan's agricultural research from 1950 to 1970. This research originated in the context of Taiwan's land reform and diversification programs and their connections to the government's political ambition to maximize food production. The study of how multiple cropping was politicized and depoliticized by different actors helps to expand the narratives of the Green Revolution in Asia, analyze their legacies, and highlight Taiwan's role in the international exchange of visions of agricultural development during the Cold War.Summary Scholars have recently expanded the history of the Green Revolution to move beyond the narrative of North–South technological diffusion. This article enriches the scholarship with the case of multiple cropping in Taiwan and its connection to Cold War geopolitics. Rice productivity in postwar Taiwan was boosted through a land reform launched by the Sino‐American Joint Commission on Rural Reconstruction (JCRR) in the 1950s. Backed by American aid and staffed by scientists from the Republic of China (ROC) government, the JCRR envisioned to turn tenant farmers into landowners so as to encourage labor input and adoption of seeds and fertilizers. By 1960, the JCRR presented its reform as a “bloodless social revolution” and extended its focus to multiple cropping through a diversification program. The JCRR further created the Asian Vegetable Research and Development Center (AVRDC) in 1971 to spread Taiwan's breeding and cropping techniques. The ROC's diplomatic isolation in the 1970s, however, prompted the center to reinterpret Taiwan's success in multiple cropping from a political achievement to a technological triumph, thus reinforcing the technology‐driven narrative used by the International Rice Research Institute (IRRI). Through Taiwan's influences on IRRI's rice breeding and multiple cropping research, this paper illustrates that the history of the Green Revolution requires more complex narratives. In addition, with Taiwan's political and economic transition since the 1980s, farmers began to reclaim their voice and influence agricultural policies. The case thus highlights the need of democratic participation in agricultural research, a concern that remains relevant today.

With and against the Grain

Abstract This article studies the Asian Vegetable Research and Development Center (AVRDC) in Taiwan. It begins with the Sino-American Joint Commission on Rural Reconstruction (JCRR), a US-funded agency championing plant breeding and land reform. Capitalizing on Japanese colonial legacy, a technocratic Chinese nationalism, and Cold War geopolitics, the JCRR boosted the productivity of rice while diversifying the agricultural economy through vegetable cultivation. The AVRDC, supported by the Rockefeller Foundation and the US government, was created in 1971 to bring this vision to Southeast Asia. The expulsion of Taiwan from the United Nations nonetheless threatened the center's survival. To carve out its sphere of influence, the AVRDC combined vegetable breeding programs with experiments on home gardening and small-scale agriculture, inserting itself into a bourgeoning sustainability discourse in the 1980s. The article argues that the center's ambiguous position within the international agricultural research network prompted it to adopt a “modest narrative” that celebrated not heroic figures but the collaborative endeavor of scientists sympathetic to farmers. However, the marginalization of agriculture and shifting identity politics in Taiwan made the center's achievement increasingly less relevant to its host country, thus complicating the significance of the AVRDC to the agricultural history of Taiwan.

The study of economically valuable traits of sweet pepper collection varieties and effectiveness economic evaluation of their cultivation in the conditions of protected ground in Armenia

In the conditions of an unheated film greenhouse 14 collection sweet pepper (Capsicum annuum L.) samples were studied: Darovita F1, N-62-439 (Nickerson-Zwaan), Yupiter F1, Dimentio F1, Blondi F1 (Syngenta), AVPP 0503, AVPP 0709, AVRDC-9946-2192, PBC-371, AVPP 0408, AVRDC-0701, AVPP 0910, AVPP 1115, AVPP 05483 - from genbank of AVRDC (Asian Vegetable Research and Development Center). According to the duration of the phenophases, 11 samples were assigned to the group of mid-ripening and 3 samples were classified as late-maturing. The varieties differed in shape, color, average weight of the fruit (within 76.1 to 208.4g). The total yield of variety samples varied from 8.9 to 15.9 kg/sq m, with the control variety “Sate”- 11.5 kg/sq m. Varieties AVPP 05483, N-62-439, AVPP 0503, AVRDC 0701 turned out to be the most highly productive, in which the increase to the standard was 20.9, 22.6, 33.0, 38.3% and profitability of cultivation was 125.6, 120.3, 129.1, 130.7% respectively. Variety samples from AVRDC AVPP 0503 with the name “Narinj” and AVRDC-0701 - “Loshtak” passed the State Variety Testing and are now successfully cultivated in greenhouses of Armenia.

RESPONSE OF Ty-RESISTANT TOMATO (Solanum lycopersicum) CULTIVARS TO BEGOMOVIRUSES AND THEIR GAS CHROMATOGRAPHY MASS SPECTROMETERY ANALYSIS

Tomato (Solanum lycopersicum) production is affected by different diseases andTomato yellow leaf curl virus (TYLCV) is the most prevalent and devastating begomovirus. Tyresistant cultivars were developed by Asian Vegetable Research and Development Center (AVRDC)Taiwan, using different combinations of Ty genes to observe pyramiding effects on resistance againstvarious Begomoviruses. Cultivars containing Ty genes were grown in glass house at 65% relativehumidity, 16 hours Dark and 8 hours Light, at 26 oC. At the age of 5 to 6 leaves, plants were exposed toviruliferous whitefly and were kept for ~40 days. Symptoms were observed every 10 days postexposure. Among nine Ty-resistant and one native (Nagina) cultivars, three were resistant i.e., R1, R6and R9, two mild to moderately resistant i.e., R2 and R10, three i.e., R7, R8 and R14 very mildresistant while one Ty cultivar i.e., R15 along with susceptible (Nagina) variety showed no resistance.Nagina (susceptible) and R6 (resistant) cultivars were analyzed by Gas Chromatography MassSpectrometry (GCMS). Among Ty cultivars (Ty-2, Ty-3 and Ty-5) genes harbouring cultivars showedbetter resistance and GCMS analysis lead to identification of bioactive compounds associated withresistant (R6) cultivar.

Germplasm Introduction and Genetic Divergence in Amaranth

ABSTRACTDevelopment and evaluation of genetic diversity is necessary for selection decisions in breeding. Amaranth (Amaranthus spp.) is used as vegetable in the human diet. Thirty-one genotypes of amaranth, collected from the Asian Vegetable Research and Development Centre (AVRDC), Tanzania; Research Institute and Crop Production (RICP), Czech Republic; National Centre for Genetic Resources and Biotechnology (NACGRAB), Nigeria; and National Horticultural Research Institute (NIHORT), Nigeria, were evaluated for grain yield and related characters. Entries were evaluated in 2012 to determine genetic diversity among germplasm. There was a Genotype × Location interaction for most traits. Genotype Z150 from RICP had the highest grain yield at Ibadan; NG103 from NACGRAB had the highest value at Abeokuta (48.8). Genetic divergence was generally similar among germplasm from the same collection center, though a few clustered irrespective of collection center. High Mahalanobis squared distance (D2) occurred between cluster III and cluster IV (39.84). Genotypes in cluster IV were related to high grain yield (47.47 g); cluster I was associated with low days to 50% flowering (64.0). Introduction of germplasm from different geographic collection centers offers opportunity for genetic diversity and improvement of amaranth.

PHENOTYPIC EVALUATION OF FIFTEEN GLYCINE MAX (L.) MERRILL (VEGETABLE SOYBEAN) VARIETIES UNDER MINERAL AND BRIS SOILS OF MALAYSIA

Glycine max (L.) Merrill (vegetable soybean) is an important vegetable mainly among the Asian community. It is mainly consumed by human as a highly nutritious and savory snack. Instead of having a relatively higher protein and lower oil contents, it is also has a sweet and better tasting. Thus, this study aims to investigate the phenotypic characteristics of fifteen varieties of Glycine max (L.) Merrill developed by the Asian Vegetable Research and Development Center (AVRDC), Taiwan in order to select the potential varieties to be planted under Malaysian environments. The fifteen varieties were planted under mineral and bris soils at International Islamic University Malaysia (IIUM) Kuantan, Pahang. Eight phenotypic traits included the seed numbers per plant, the pod numbers per plant, the weight of fifteen seeds per plant, the days to emergence per plant, the days to flowering per plant, the plants height per plant, the pods width per plant and the pods length per plant were measured. Selection of potential varieties were mainly done by determining the yielding characteristics. Among these eight morpho-agronomic characteristics, the seed numbers per plant is the main yield determinant while, the other characteristics would be useful for future breeding programs. From the observation, Variety 4 (AGS429) obtained the highest seed numbers per plant (81 seeds) under mineral soil and Variety 1 (AGS 190) produced the highest seed numbers per plant (91 seeds) under bris soil, thus having the promising higher yielding ability to be selected as a potential vegetable soybean varieties to be planted under Malaysian conditions.

주요 오이 품종의 노균병에 대한 저항성 검정

본 연구는 국내 수집 및 아시아채소개발센터 보유 품종인 오이 22종을 이용하여 노균병에 대한 품종별 저항성 정도를 구명하고 우수 품종을 선발하고자 대만 타이난소재 아시아 채소연구 개발 센터에서 수행하였다. 수집 품종에 대한 노균병 병원균 접종은 모든 수집 품종의 생장 단계 중 유엽이 5-6엽 전개되는 유묘 초기에 병원균을 접종하여 검정하였다. 이때 노균병 발병에 최적 발병조건 유지를 위해 온도 조절이 가능한 항온기 내에서 처리 후 일정기간 유지하였다. 노균병균의 접종농도는 <TEX>$1{\times}10^5$</TEX> spores/ml의 포자 현탁액을 오이 잎에 1회 분무 접종 후 잎에 발생한 병반수를 6, 9, 12, 15일 총 4회에 걸쳐 조사하였다. 그 결과 <TEX>$15^{\circ}C$</TEX>와 <TEX>$25^{\circ}C$</TEX> 챔버에서는 병반 형성이 매우 낮았으나 <TEX>$20^{\circ}C$</TEX> 처리에서는 처리 품종당 평균 병반수 20-30개(5엽 기준)를 나타내어 병반 형성이 비교적 높았다. 처리 품종별 병반수는 'C-19' 품종에서 0.90(10-20% 미만)로 다른 품종에 비하여 비교적 병반수가 낮아 노균병에 대한 가장 높은 저항성을 나타내었다. 기타 품종에서는 병반수가 다량 형성되어 노균병에 대한 저항성이 낮았으며 처리 후 경과일수가 길어질수록 더욱 증가되어 유의적인 차이는 나타나지 않았다. This study was carried out for the downy mildew resistant test between 2010 and 2012. A set of 22 accessions belonging to 2 wild species and 20 varieties of the genus Cucumis, originating mainly from the Asian Vegetable Research and Development Center (AVRDC) Gene Centre, was evaluated for resistance to Pseudoperonospora cubensis, causal agent of cucumber downy mildew. The youngest fully expanded true leaves were found suitable for in vitro screening. Both leaf discs and full leaves could be kept fresh longer when applying 0.2 <TEX>${\mu}g/ml$</TEX> of gibberellin acid (GA). The incubation temperature of <TEX>$20^{\circ}C$</TEX> was found to be the most suitable temperature for symptom development comparing with 15 and <TEX>$25^{\circ}C$</TEX>. Symptom development was faster when contact diseased leaf discs (2 weeks after inoculation) on to fresh leaf samples comparing with using conidia suspension (<TEX>$10^5$</TEX> spores/ml). The numbers of spots in 'C-19' were lower than other varieties. 'C-19' variety was also showed the highest level of downy mildew resistant at <TEX>$20^{\circ}C$</TEX> chamber in 6 days after inoculating with pathogen and displayed 0.90 (under 10%) of the infected rate. However, other varieties displayed susceptible in the pathogen sprayed plots. 'C-19' was the most resistant variety and no lesion was observed. Based on all data, 'C-19' can be a useful variety for the prevention of downy mildew.

Productivity of determinate growth tomato lines tolerant to heat under the organic system

The objective of the present work was to evaluate the productive response of heat tolerant lines of determinate growth tomato under the organic production system. The experiment was carried out in the Instituto de Ciências Agrárias of UFMG, Montes Claros, Minas Gerais state, Brazil. The experimental design was of randomized complete blocks with eight treatments and four replications. The treatments consisted of eight heat tolerant processing type tomato lines obtained from the Asian Vegetable Research and Development Center (AVRDC), China: CLN1621L, CLN1621F, CLN1621E, CLN1466P, CLN2026E, CLN2026D, CLN2026C and CLN2001C. There was an inverse relationship between the average weight of the fruits and the number of fruits per plant. The highest average fruit weight of some lines was compensated by the lowest quantity of fruits, in such a way that there were no significant differences among the lines. Symptoms of nutritional deficiency and incidences of pests and diseases were not verified in any of the studied lines. All lines presented potential for genetic improvement research and cultivation using organic production systems under higher temperature conditions.

Natural Variation of Folate Content and Composition in Spinach (Spinacia oleracea) Germplasm

Breeding to increase folate levels in edible parts of plants, termed folate biofortification, is an economical approach to fight against folate deficiency in humans, especially in the developing world. Germplasm with elevated folates are a useful genetic source for both breeding and direct use. Spinach is one of the well-know vegetables that contains a relatively high amount of folate. Currently, little is known about how much folate, and their composition varies in different spinach accessions. The aim of this study was to investigate natural variation in the folate content and composition of spinach genotypes grown under controlled environmental conditions. The folate content and composition in 67 spinach accessions were collected from the United States Department of Agriculture (USDA) and Asian Vegetable Research and Development Center (AVRDC) germplasm collections according to their origin, grown under control conditions to screen for natural diversity. Folates were extracted by a monoenzyme treatment and analyzed by a validated liquid chromatography (LC) method. The total folate content ranged from 54.1 to 173.2 μg/100 g of fresh weight, with 3.2-fold variation, and was accession-dependent. Four spinach accessions (PI 499372, NSL 6095, PI 261787, and TOT7337-B) have been identified as enriched folate content over 150 μg/100 g of fresh weight. The folate forms found were H(4)-folate, 5-CH(3)-H(4)-folate, and 5-HCO-H(4)-folate, and 10-CHO-folic acid also varied among different accessions and was responsible for variation in the total folate content. The major folate vitamer was represented by 5-CH(3)-H(4)-folate, which on average accounted for up to 52% of the total folate pool. The large variation in the total folate content and composition in diverse spinach accessions demonstrates the great genetic potential of diverse genotypes to be exploited by plant breeders.

NC 1 CELBR and NC 2 CELBR: Early Blight and Late Blight-resistant Fresh Market Tomato Breeding Lines

NC 1 CELBR and NC 2CELBR are sister lines developed in a long-term breeding program in North Carolina to combine early blight and late blight resistances into adapted fresh-market tomato backgrounds. The pedigree of the two breeding lines traces back to NC 215E-1(93), a large-fruited determinate line with moderate resistance to the foliage blight phase of early blight and high resistance to the stem lesion phase of early blight (Fig. 1). NC 215 E-1(93) has a complex pedigree extending back to NC EBR-1, which has moderate foliage resistance to early blight derived from the Lycopersicon hirsutum L. (currently Solanum habrochaites S. Knapp & D.M. Spooner) source PI 126445 and NC EBR-2, which has moderate foliage resistance and a high level of stem lesion resistance to early blight derived from Campbell 1943 (Gardner, 1988). The Ph-2 gene for late blight resistance was derived from Richter’s wild tomato, and the Ph-3 gene was derived from L. 3707, a selection of the Lycopersicon pimpinellifolium L. (currently Solanum pimpinellifolium L.) line PI 365957 obtained from the Asian Vegetable Research and Development Center (AVRDC). The Ph-2 and Ph-3 genes from these small-fruited sources were backcrossed into NC 215E-1(93) to develop large-fruited lines, which were then crossed to combine the Ph-2 and Ph-3 genes into the early blight resistant background derived from NC 215E-1(93). The resultant F1 hybrid, NC 03220, was selfed, and 96 F2 generation plants were tested in growth chambers using detached leaf inoculations (Brusca, 2003) for combined resistance to isolates (Ph2-OC and Ph3-OC) that specifically overcame Ph-2 and Ph-3. Plants exhibiting a high level of resistance to inoculation with the two isolates (Ph2-OC and Ph3-OC) separately and in combination were selfed in the greenhouse, and F3 generation plants were evaluated in the field for combined resistance to early blight and late blight. Selections were made in the field for the best horticultural traits, including fruit size and smoothness combined with resistances to early blight and late blight. The field selections, 33EB-1(2004) and 45EB2(2004), leading to NC 1 CELBR and NC 2 CELBR, respectively, were derived from a single F2 plant that was homozygous for the Ph-2 and Ph-3 genes combined based on field trials in 2004 and subsequent years and verified by detached leaf inoculations in the growth chamber (Brusca, 2003).

Heredity Analysis and Gene Mapping of Bruchid Resistance of a Mungbean Cultivar V2709

Bruchid is a serious insect pest of mungbean [ Vigna radiata (L.) Wilczek] and can inflict serious loss. A resistant variety from India, V2709, was crossed with a susceptible variety, Zhonglü 1, from the World Vegetable Center, Asian Vegetable Research and Development Center (AVRDC). Segregation of the F 2, BC 1F 1, and F 3 populations showed that bruchid resistance of V2709 is controlled by a single dominant locus. To find molecular marker linked with the resistant locus, 63 randomly amplified polymorphic DNA markers and 113 sets of SSR/STS primers were used in a bulked segregant analysis. Two of the markers, OPC-06 and STSbr2, were found to be linked with the locus (named as Br2). Further analysis suggested that the genetic distances between these two markers and Br2 were 11.0 and 5.8 cM, respectively.

Comparison of Morphological and Genetic Characteristics of 15 Sweetpotato [Ipomoea batatas (L.) Lam] Accessions Grown on Guam

Fifteen sweetpotato [Ipomoea batatas (L.) Lam] accessions grown on Guam were studied for morphological and genetic characteristics. Accessions, obtained from AVRDC (Asian Vegetable Research and Development Center) in Taiwan, Saipan, Rota, and Guam, were investigated for marketable yield, growth habit and characteristics of tuberous roots (color, shape, sugar content and moisture content). Results of this study were used to determine the morphological relationship of the accessions of sweetpotato. Phenetic analysis revealed four major clusters according to tuberous root characteristics. The genetic relationship of these sweetpotato accessions was also evaluated for genetic differences among accessions. DNA was extracted and went through polymerase chain reaction (PCR). PCR products were analyzed by random amplified polymorphic DNA (RAPD) fingerprinting. Result of the genetic relationship among the sweetpotatoes was compared with the morphology of accessions using UPGMA cluster analysis and principal compounds analysis.

Developmental Characteristics of Diadegma semiclausum Hellen (Hymenoptera: Ichneumonidae), a Larval Parasitoid of Plutella xylostella L. (Lepidoptera: Yponomeutidae)

Some developmental characteristics of a larval-parasitoid ichneumonid, Diadegma semiclausum Hellen, donated from Asian Vegetable Research and Development Center (AVRDC), Taiwan, in 2001, were investigated to utilize as a biological control agent of diamondback moth (DBM), Plutella xylostella L. As a preliminary test for rearing the prey insect, we selected the most preferable host plant for oviposition. Among five host plants tested, DBM female laid the highest number of eggs on the aluminum foil prepared with radish leaf juice, followed by rape, Chinese cabbage, broccoli and common cabbage. The developmental periods for the whole larval stage of D. semiclausum and DBM were 12.3 days and 14.2 days at 23°C, respectively. Also, parasitoid cocoons could be stored at 8°C for 24.5 days without a significant loss of viability. The DBM pupa, however, lasted for approximately four weeks at 8°C. The percent parasitism to DBM was 70.8% on average, and the sex ratio of D. semiclausum adults was slightly male-biased, 0.94:1. The seasonal fluctuation of DBM density showed apparently two generations, and the peak periods occurred in middle June and middle July.

Population changes in Phytophthora infestans in Taiwan associated with the appearance of resistance to metalaxyl.

In recent years, late blight, caused by Phytophthora infestans (Mont) De Bary, has increased in severity in many parts of the world, and this has been associated with migrations which have introduced new, arguably more aggressive, populations of the pathogen. In Taiwan, late blight has been endemic on outdoor tomato crops grown in the highlands since the early 1900s, but recent epidemics have been more damaging. To ascertain the present status of the Taiwanese population of P infestans, 139 isolates of the pathogen collected and maintained by the Asian Vegetable Research and Development Center (AVRDC) were characterized using mating type, metalaxyl sensitivity, allozyme genotype, mitochondrial haplotype and RFLP fingerprinting. Up to 1997, all isolates were found to belong to the old clonal lineage of P infestans (US-1 and variants), but in isolates from 1998 a new genotype appeared, and by 2000 this had apparently completely displaced the old population. This new genotype was an A1 mating type and has the dilocus allozyme genotype 100/100/111, 100/100 for the loci coding for glucose-6-phosphate isomerase and peptidase, respectively. These characters, together with RG57 fingerprinting, indicated that these isolates belonged to the US-11 clonal lineage, a minority (11%) being a previously unreported variant of US-11. Whereas metalaxyl-resistant isolates were not detected in the old population, 96% of the new genotypes proved resistant, with the remainder being intermediate in sensitivity. It may be inferred from this sudden, marked change in the characteristics of the Taiwanese P infestans that a new population of the pathogen was introduced around 1997-98 and that this may well have already been metalaxyl-resistant when it arrived, although a role for in situ selection cannot be excluded.

Comportamento de linhagens de feijão-mungo(Vigna radiata L.) em Santa Catarina

Foram conduzidos três experimentos na fazenda experimental do Centro de Ciências Agrárias da Universidade Federal de Santa Catarina, Florianópolis, SC, Brasil. A finalidade do trabalho foi avaliar o comportamento de 29 linhagens de feijão mungo provenientes do "Asian Vegetable Research and Development Center" (AVRDC). Avaliaram-se as características agronômicas (formacão da primeira flor, primeiro legume maduro, estatura da planta), o peso de mil sementes e o rendimento. As linhagens foram testadas em blocos ao acaso, com quatro repetições. Cada parcela foi constituída por 4 linhas de 6m de comprimento, espaçadas de 50cm, com vinte sementes por metro de sulco. A floração inicial das linhagens ocorreu entre os 33 e 49 dias após o plantio, enquanto a maturação do primeiro legume se deu entre os 70 e 78 dias após a semeadura. A estatura das plantas e o peso de mil sementes variaram entre 22,5 e 63,8cm e 33,0 e 76,4g respectivamente. As linhagens mais produtivas foram: VC 3890B, VC 1973C e VC 2764B com rendimento acima de 1140kg.ha-1. Estas linhagens apresentaram peso de mil sementes e estatura de planta boas para cultivo e um ciclo biológico médio. A colheita foi feita em uma única operação, entre 80 e 85 dias após a semeadura no primeiro e segundo experimentos. No terceiro experimento, a colheita foi feita em duas vezes, aos 80 e 85 dias e aos 95 e 100 dias, sendo que na primeira colheita foram colhidos 78% dos legumes; os restantes 22% foram colhidos 15 dias após a primeira.

Ouro Verde MG 2: nova cultivar de mungo-verde para Minas Gerais

Dentre várias linhagens introduzidas do "Asian Vegetable Research and Development Center" (AVRDC), sobressaiu a linhagem VC 3984-B-2-B-4-1-B, que recebeu o nome de Ouro Verde MG 2. Suas sementes são verde-brilhantes e o peso de 1000 unidades varia de 43 a 51 g. O início da floração ocorre em torno de 33 dias após a emergência e a primeira vagem madura surge entre 23 e 33 dias. Por se tratar de espécie de maturação desuniforme, podem ser necessárias duas a quatro colheitas. As plantas podem atingir 95 cm de altura. As vagens são marrom-escuras e concentram-se na parte superior da planta. É suscetível a duas doenças que geralmente aparecem no final do ciclo de vida do mungo-verde: míldio-pulverulento (Erysiphe polygoni) e mancha-foliar-de-cercospora (Cercospora canescens). A 'Ouro Verde MG 2' é resistente ao acamamento, e o seu rendimento, em três ensaios instalados em dezembro, janeiro e fevereiro, variou de 1,5 a 2,0 t/ha. Esses rendimentos foram, em média, 12% superior ao da cultivar Ouro Verde.

Gene Action and Heritability of High-temperature Fruit Set in Tomato Line CL5915

High-temperature fruit set (heat tolerance) is a critical trait of tomato (Lycopersicon esculentum Mill.) cultivars targeted for lowland wet season production in the tropics and subtropics. Heat-tolerant Asian Vegetable Research and Development Center (AVRDC) tomato line CL5915-93D4-1-0-3 (CL5915) is a valuable source of heat-tolerance genes for tomato genetic improvement. The gene action of heat tolerance in CL5915 was determined by evaluating the F1, F2, BCP1, and BCP2 of a cross between CL5915 and heat-sensitive line UC204A for fruit set traits in two wet-season trials at AVRDC. Parent-offspring regression of F2-derived F3 (F2:3) family means on the F2 plants from CL5915 × UC204A was used to estimate the heritability of F2 single plant selection for heat tolerance. Mean percentage of fruit set and fruit number per cluster of the F1 and BCP1 exceeded midparent values and were not significantly different from those of CL5915, indicating complete dominance for heat tolerance. Generation means analyses indicated that a model including simple additive and dominance effects adequately explained the inheritance of mean fruit number per cluster both years. For mean percentage of fruit set, a model including simple additive-dominance effects produced an adequately fitting model in the 1996 season but the best-fitting model included an epistatic component in the 1997 season. Heritabilities estimated for fruit set traits in 1996 and 1997, respectively, were: 0.31 and 0.21 for percentage of fruit set; 0.28 and 0.14 for mean fruit number per cluster; and 0.53 and 0.15 for flower number per cluster. The low heritabilities for percentage of fruit set and mean fruit number per cluster under high temperatures imply that single plant selection in the F2 for heat tolerance from crosses involving CL5915 is not effective and that selection should be based on replicated family testing in the F3 and later generations.

552 Comparison of Genetic Diversity in between Two Germplasm Banks Containing Lycopersicon esculentum Accessions

Worldwide, there are cuurently more than 60 germplasm banks that contain tomato (Lycopersicon esculentum) collections ranging is size from a few dozen to several thousands of accessions. In the utilization of these genetic resources sampling from only one germplasm bank may result in limiting available genetic diversity, whereas sampling from several germplasm banks may result in unnecessary redundancy. The current lack of knowledge regarding the relative magnitudes of genetic diversity contained within different collections makes it difficult to develop a core collection that maximizes genetic diversity. Two large tomato collections are housed at the Asian Vegetable Research and Development Center (AVRDC), Sanhua, Taiwan, R.O.C., and the Centro Agronomico Tropical de Investigacion y Enseoanza (CATIE), Turrialba, Costa Rica. Ninety-six accessions from CATIE and 102 accessions from AVRDC were randomly sampled from each base collection. The total of 198 accessions were charcterized for 103 polymorphic RAPD molecular marker bands. The results indicated that the two germplam banks sampled different genetic diversity. In addition, the magnitude of genetic diversity was greater in the AVRDC collection compared to CATIE.

The Integrated Research Approach of the Asian Vegetable Research and Development Center (AVRDC) to Enhance Micronutrient Availability

This paper describes various activities of the Asian Vegetable Research and Development Center (AVRDC) in enhancing micronutrient availability through increased vegetable supply, improved micronutrient density in vegetables, enhanced micronutrient bioavailability, and recommendations for programmes and policies generated through economic research. Technological, nutritional, and socio-economic research are integrated at AVRDC. Nutrient considerations are incorporated at all levels of research planning, technology development, and dissemination of these technologies to clients. The approach ensures not only greater diversity and improved palatability of food, but also enhanced income and employment to poor farming and landless households and improved gender equity. All these factors are catalysts to improved health as well as faster economic growth for developing economies. To tackle widespread micronutrient deficiencies, future nutritional research should focus on making improved vegetable technologies economically viable under a wider range of economic and ecological environments, while enhancing or, at minimum, maintaining the nutrient density and bioavailability of new vegetable releases. To improve the efficiency of nutritional research, the dollar value of micronutrient enhancement research needs to be quantified and compared for different vegetables and other food items. A methodology for doing this is proposed and illustrated.

Genetic Variation among Tomato Accessions from Primary and Secondary Centers of Diversity

The Asian Vegetable Research and Development Center (AVRDC) maintains one of the largest collections of Lycopersicon germplasm. Approximately 60% of the collection is from Old World regions; however, it is unclear whether these accessions represent unique sources of genetic variation compared with accessions from New World regions. The objective of this study was to compare the magnitude and structure of genetic variation among tomato accessions collected from Old and New World regions. Forty‐one random amplified polymorpbic DNA (RAPD) primers generated 98 polymorphic RAPD markers and were used to estimate relationships among 96 accessions collected from a wide geographic range. Genetic distances, marker frequency, and marker diversity were used to compare subpopulations of these accessions. Differences in RAPD marker frequencies indicated uniqueness of accessions from the New and Old World collections. In addition, accessions from Ecuador, Peru, and Chile had a larger magnitude of marker diversity than do Old World accessions. Comparison of sub‐populations of L. esculentum and its sub‐species, L. esculentum var. cerasiforme, indicated that the two are distinct but have similar levels of diversity. Variation among L. esculentum accessions can be obtained at a faster rate by sampling accessions from the primary center vs. other geographic regions. Yet Old World accessions complement accessions from the New World and are not simply redundant sources of variation.