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Ruth S. Kobayashi, Stephen L. Sinden, and John R. Stommel

Incorporation of genes from wild species has been a major contributor to tomato improvement in recent years. Solanum ochranthum, a woody non-tuber bearing species, is a potential source of resistance against tomato diseases and insect pests but is genetically isolated from tomato. Somatic hybridization methods were developed to facilitate the use of S. ochranthum for tomato germplasm improvement. Leaf mesophyll protoplasts of S. ochranthum and a Lycopersicon esculentum hybrid were chemically fused with polyethylene glycol. The protoplasts were initially cultured in Shepard's CL, a MS based medium, containing 1 mg·1-1 NAA, 0.5 mg·1-1 BAP and 0.5 mg·1-1 2,4-D. Hybrid regenerants and regenerants of the L. esculentum parent were recovered; S. ochranthum did not regenerate. Hybridity was established by morphological characters, peroxidase isozyme and RAPD markers. Use of these somatic hybrids for tomato improvement was evaluated.

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Serudin Tinggal and Thean S. Tee

Magifera panjang Kostermans, indigenous to Brunei is widely adapted to lowland and hilly areas. The vigorous tree grows tall (30 - 40 metres high). Grafting on M. indica stock or own stock has dwarfing effect and shortens juvenile stage to stimulate fruit production within 5-6 years. The obicular fruits are large with tough brown skin. The thick golden yellow flesh is juicy, pleasant to eat, having aromatic fragrance. Some cultivars are less fibrous. The fruit has wide traditional usage and demand is seemingly unsatisfiable.

Mangifera pajang is quite tolerant to various diseases affecting mangoes. Insect pests do not appear to damage the trunk or the fruits.. The blossoms on stout and erect flowering spikes attract a host of pollinators. Anthracnose problem is unknown even in the wet season. These features are useful for possible transfer to the more susceptible M. indica cultivars.

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M.J. Else

In Integrated Pest Management (IPM), the costs of a control measure are compared to the potential for economic losses caused by a pest, with control measures being recommended only when expected costs of losses exceed costs of control. IPM models have been developed largely for insect pests, which multiply rapidly and for which timely population assessments are thus essential. Weed pests, on the other hand, multiply slowly. In the case of perennial crops, weeds may not reach populations sufficient to warrant control under conventional IPM criteria for many years. It is proposed that IPM concepts be adapted to weedy pests of perennial crops by creating models in which the long-term costs and consequences of both weeds and weed control measures are considered. These models would take into account expected increases in control costs and decreases in effectiveness of control measures over time and as a consequence consider some weeds to have effective thresholds at or near zero.

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Han Yulin, Ha Huiquan, Xin Huipu, Zhao Pengxiang, and Shi Xinwei

Stevia rebaudiana Bertoni was hydroponically raised on the matrices of sand or slag and sprinkled periodically with three different nutrient solutions (BD, KO, Knop) respectively. The conventional raising method of Hailin state farm was used as the control. The results showed that the seedlings grown on the matrix of sand and sprinkled with Knop nutrient solution were stronger with well-developed root systems, obvious spindle-shaped root tubers, and less plant diseases, no insect pests, and weeds, which was significantly better than the control method in respect to the root length, root fresh weight, stem height, shoot fresh weight, and number of leaves, and significantly better than other treatments in respect to the root length, root fresh weight and stem height. This raising method is worth extending.

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K.B. Paul

Most farmers in Sub-Saharan Africa plant local cultivars introduced generations ago. Various national and international organizations and development projects introduce annually hundreds of improved germplasms to a country, and test these under farmer conditions for adaptability and acceptability. Although some local varieties perform well under traditional farming practices, many disease and insect pest resistant improved varieties out-yield local cultivars even under low-input production conditions of Africa. Regrettably, the seed production and distribution system in most of these countries are poorly developed; thus the promising varieties remain unavailable to the majority of farmers. To overcome this problem, the University of Arkansas-led Rwanda Farming Systems Research Project (FSRP) personnel trained farmer-cooperators in the production of good quality bean (Phaselous sp.) seeds. This, and the development of a farmer to farmer seed distribution system that led to quick diffusion of improved bean varieties in the project area will be discussed.

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G.R. Brown, J. Hartman, R. Bessin, T. Jones, and J. Strang

Apple growers would like to use pesticides efficiently and diminish concerns about food safety and pesticide usage. The 1992 Apple IPM Program objectives were: 1) to demonstrate the application of Integrated Pest Management practices in commercial orchards and, 2) to provide the training and support needed to help these growers become self sufficient in IPM practices. Grower training meetings and regular scouting of the orchards were the primary educational methods. End-of-the-season evaluations of past and disease incidence were made. Except for Frogeye Leaf Spot, there were no significant differences in insect pest, disease levels or in fruit quality attributes in IPM versus standard blocks. The IPM blocks had significantly more mite incidence. Growers did produce commercially acceptable crops using IPM based decisions while reducing the average past control cost by $56 par acre. Educational programs did help growers to be more proficient in making IPM based decisions.

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R. L. Fery and P. D. Dukes

The Agricultural Research Service of the United States Department of Agriculture announced the release of `Bettergro Blackeye' southernpea on 24 July 1991. The new cultivar is well adapted for production throughout the southern United States where it can be expected to produce excellent yields of high quality, blackeye-type peas. `Bettergro Blackeye' outyielded the `Pinkeye Purple Hull-BVR' check in the 1986, 1987, 1988, and 1989 Regional Southernpea Cooperative Trials by 34.8, 14.3, 12.6, and 20.9%, respectively. Canned samples of fresh `Bettergro Blackeye' peas scored well in three years of quality evaluation tests. The new cultivar is resistant to the cowpea curculio, the major insect pest of the southernpea in southeastern production areas, and root knot, a severe root disease incited by several species of the root-knot nematode. `Bettergro Blackeye' plants have a greater tendency to produce a second crop than plants of most southernpea cultivars.

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Megan Ulmer, Regina Ali, Conrad Bonsi, Louis Jackai, and Bryon Sosinski

The sweetpotato weevil (SPW), Cylas formicarius, is the most devastating insect pest of sweetpotato worldwide. In the U.S., the devastation by this pest costs the sweetpotato industry several million dollars in crop loss and lost income each year. Many growers in highly infested areas have simply abandoned growing sweetpotatoes. The overall project goals are to elucidate the routes used for the spread of the SPW, and to determine the existence of intra-specific variation in the SPW population in the US and selected overseas countries. These results will lead to more effective and targeted management of the SPW. Results will also make quarantine enforcement more efficient. We are examining the highly conserved and phenotypically neutral rDNA sequences of both the 18S and ITS1 regions of the SPW genome as a way to determine the population structures and origins of SPW in the US. Here, the molecular genetic aspects of the project are outlined, and preliminary results are presented.

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Raúl Leonel Grijalva-Contreras, Arturo López-Carbajal, Adán Fimbres-Fontes, Cristobal Navarro-Ainza, Rogelio Juárez-González, and Fabián Robles-Contreras

Apricot production in México is limited; actually, the area devoted to this crop is ≈880 ha, from which 230 ha are established in Sonora State. The main cultivar is `Canino'. The fruit yield ranges from 15 top 20 t·ha-1. The present study tested 20 low-chilling (300-400 chill hours) requirements of apricot selections; `Nemaguard' was the rootstock used. On the fourth production year, from the 20 apricot selections tested, 7-23, 1-81, and 15-1 yielded 31.8, 20.2, and 15.5 t·ha-1, respectively. all of these selections showed higher yields than `Canino' (14.6 t·ha-1). The fruit of these apricot selections ripened by mid-May, exhibiting a similar fruit quality (size, flavor, color, and °Brix) in all the tested selections. We have not recorded any important insect pests or diseases during this trial.

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Raúl Leonel Grijalva-Contreras, Arturo López-Carbajal, Adán Fimbres-Fontes, Cristobal Navarro-Ainza, Rogelio Juárez-González, and Fabián Robles-Contreras

Apricot production in México is limited; actually, the area devoted to this crop is ≈880 ha, of which 230 ha are established in Sonora State. The main cultivar used is `Canino'. The fruit yield ranges from 15-20 t·ha-1. The present study tested 20 low-chilling (300 to 400 chill hours) requirments of apricot selections; `Nemaguard' was the rootstock used. On the 4rth production year from the 20 apricot selection tested, 7-23, 1-81, and 15-1 yielded 31.8, 20.2. and 15.5 Ton.Ha-1, respectively; all of these selections showed higher yields than the Canino cultivar (14.6 t·ha-1). The fruit of these apricot selectiosn ripened by mid-May, exhibiting all the tested selection a similar fruit quality (size, flavor, color, and °Brix). We have not recorded any important insect pests or diseases during this trial.