Good Quality Seeds Research Articles

Pearl Millet: A Compulsory Crop in Hyper Arid Zone 1C

Pearl millet [Pennisetum glaucum (L.) R. Br.] a is diploid (2n=14), and one of the most drought tolerant cereal crop grown in India, West Africa, Pakistan and Southern Asia. It is grown where nothing can be grown. Pearl millet is the most widely grown species of millet, grown in India and Africa since prehistoric times. It is now generally accepted that pearl millet originated in Africa and that it was introduced into India from there. Pearl millet is well adapted to production systems characterized by low rainfall, low soil fertility, and high temperature, and thus can be grown in areas where other cereal crops, such as wheat or maize, would not survive. Today pearl millet is grown on over 26 million hectares worldwide. In Zone 1C, it is predominantly grown as a grain crop but is also valued for its fodder. The pearl millet grains forms the staple diet while fodder is important for livestock s belonging to these area. In spite of release of several improved hybrids in pearl millet, their spread among the farming community is negligible resulting in the wastage of huge resources spent on the development and release of such hybrids over a long period. Despite a huge institutional framework for hybrid seed production of pearl millet in private sector, availability of good quality seeds continues to be a problem for the farmers of arid zone. As a result, they prefer to rely on farm saved seeds. Seed replacement rate continues to remain in the range of 25–30 per cent, which is much below the desired level of 50 per cent. Presently the availability of hybrid seed is limited to HHB-67-improved for this zone.

Direct and residual effects of plant nutrition’s and plant growth retardants, on cottonseed

Seed quality is one of the most important factors for stand establishment in cotton (Gossypium Sp.), and the use of good-quality seeds is therefore essential to obtain an optimum plant population. Conditions prevailing during seed formation can affect the quality of seed produced, and hence crop establishment in the next growing season. These conditions can affect the germination of the seeds and the ability of the seedlings to emerge from soil. Field experiments were conducted to investigate the effect of nitrogen (N), phosphorus (P), potassium (K), foliar application of zinc (Zn) and calcium (Ca), and the use of plant growth retardants (PGR) [e.g., 1, 1-dimethyl piperidinium chloride (MC); 2-chloroethyl trimethyl ammonium chloride (CC); or succinic acid 2, 2-dimethyl hydrazide (SADH)], during square initiation and boll setting stage, on growth, seed yield, seed viability, and seedling vigor of Egyptian cotton (G. barbadense). Dry matter yield, total chlorophyll concentration, K, Zn and P-uptake plant-1, were increased with the addition of K, foliar application of Zn, and different concentrations of P (576-1728 g·ha-1 of P). Seed yield plant-1 and plot-1, seed weight, seed viability, seedling vigor, and cool germination test performance increased as a result of the addition of the high N-rate (142.8 kg·ha-1 N), the high P-rate (74 kg·ha-1 P2O5), K (47 kg·ha-1 K), and from application of Zn, and Ca and the PGR. From the findings of the present study, band application of such treatments showed improved cotton-seed yield and affected the quality of seed produced, and hence crop establishment in the next growing season.

Efeito do dióxido do carbono, temperatura e armazenamento sobre sementes de soja e micoflora associada

O desenvolvimento vegetativo e reprodutivo da planta da soja está relacionado à tecnologia de produção de sementes de boa qualidade, com vigor e livres de patogenos. Desse modo, objetivou-se neste trabalho avaliar a efeito do dióxido de carbono (CO2) associado à temperatura sobre a micoflora e a qualidade das sementes em diferentes períodos de armazenamento. O delineamento usado foi inteiramente casualizado em fatorial (2 x 3 x 4), sendo duas temperaturas (25 e 31 ºC), três concentrações de CO2 (0,0; 2,5 e 5,0 g de CO2 kg-1 de sementes) e quatro períodos de armazenamento (30; 60; 90 e 120 dias). De acordo com resultados obtidos, observou-se que o dióxido de carbono foi extremamente tóxico para os fungos Aspergillus sp., Fuzarium sp., Coletrochium sp e Penicilium sp., com 100% de inibição na concentração de 5 g de CO2 kg-1 de sementes nas temperaturas de 25 e 31 ºC. A germinação e o vigor das sementes foi preservado pelo dióxido de carbono, com germinação de 92% após o período de 120 dias de armazenamento. Enquanto, sementes armazenadas sem CO2 na temperatura de 31 ºC, a germinação foi de 44,66%. A manutenção do vigor e da germinação foi dependente da concentração do CO2 e da temperatura. O CO2 poderá ser uma tecnologia viável a ser usada para manutenção da qualidade das sementes de soja pelas unidades de beneficiamento de sementes no estado do Tocantins.

An assessment of the physiological quality of sorghum (Sorghum bicolor L Moench) seeds planted by farmers in Bomet District of Kenya

Sorghum ( Sorghum bicolor L. Moench) is an important crop that enhances food security in a region . As a food crop, sorghum is nutritious , containing starch (75- 79%) as the major component, followed by protein (6.0 -16.1%) and oil (2.1- 5.0%). Despite the crop’s versatility, it is regrettable that sorghum yields are still fairly low in Bomet District of Kenya. One of the constraints associated with low yields is the accessibility to good quality seeds by farmers . It was assumed in this study that use of low quality seed was among the factors that could be significantly affecting the low production of sorghum in the district. This study focused on the physiological quality of seed which refers to the germination capacity, viability, characteristics related to dormancy and vigour of the seed. A total of 100 farmers were interviewed and 80 seed sample s were obtained from 80 farmers. The seeds were subjected to viability and vigour quality tests. These tests included germination (as a viability test); mean germination time and electrical conductivity tests (as vigour tests). About 29% of the seed samples taken for germination test were below the laboratory standards as stipulated in the seeds and Plant Varieties Act (CAP 326). Critical electrical conductivity values and critical mean germination time values were derived during the study . In accordance with the critical values arrived at in this study, 27.5% of the seed samples showed relatively high electric al conductivity readings and 36.3% of the seed samples showed longer mean germination time. However, 11.3% of the seed samples showed high germination percentages of above 90%. Since about 29% of farmers seeds were of bad physiological quality, it was concluded that this proportion of seed can result in poor yields and hence cause food insecurity to the people of the society , and thus require s further consideration for improvement . This study recommends that further research be conducted on the genetic, physical and sanitary quality aspects of seed planted by farmers in Bomet District so that a definite conclusive statement about the quality of seed planted by farmers in the District can be made.

Mechanism of oocyte maturation and ovulation and its application to seed production in the Japanese eel

Reduction in eel resources and catches of glass eels as seedlings for aquaculture have been a serious concern in recent years in both Europe and East Asia. Thus, technical advancement to produce eel seeds for artificial cultivation is most desired. Fundamental information on oocyte maturation and ovulation and its application to artificial induction of sexual maturation are needed to produce good quality seeds of the Japanese eel. This review introduces hormonal mechanisms of cytoplasmic maturation (such as hydration, lipid coalescence, and clearing of the ooplasm) and the maturational competence (the ability to respond to maturation-inducing steroid) and nuclear maturation (germinal vesicle breakdown). In addition, previous and newly developed methods for induction of spawning have been described.

Study of water-table behaviour for the Indian Punjab using GIS

The state of Punjab (India) has witnessed a spectacular increase in agricultural production in the last few decades. This has been possible due to high use of fertilizers, good quality seeds and increased use of water resources. This increased demand of water resources has resulted in extensive use of groundwater in the central districts of the state and surface water (canals) in South-West Punjab, where groundwater is of poor quality in general. The state has been facing the twin problem of water table decline/rise in different parts. Efficient management relies on comprehensive database and regular monitoring of the resources. GIS is one of the important tools for integrating and analyzing spatial information from different sources or disciplines. It helps to integrate, analyze and represent spatial information and database of any resource, which could be easily used for planning of resource development, environmental protection and scientific researches and investigations. Geographical Information Systems (GIS) have been used for a variety of groundwater studies. Groundwater level change maps are useful in determining areas of greatest changes in storage in the regional systems. In this study, an attempt has been made to assess the long term groundwater behaviour of the state using GIS to visually and spatially analyze water level data obtained from the state and central agencies. The data was analysed for 0-3 m, 3-10 m, 10-20 m and beyond 20 m. The study revealed that per cent area with water table depth > 10 m was 20% in 1998 and has increased to 58% by 2006 which is critical limit for shifting from centrifugal pump to submersible pump.

Culling phenotypically inferior trees in seed production area enhances seed and seedling quality of Acacia auriculiformis

Improvement in seed and seedling quality of Acacia auriculiformis after culling phenotypically inferior trees was studied in a 6-year old seed production area (SPA). A 5-ha plantation was identified, of which 2.3 ha was converted into SPA. The initial stocking, 1 612 trees·ha−1, was thinned down to 982 trees·ha−1 based on growth characteristics. The following fruiting season, seeds were collected from 10 randomly selected trees in culled and non-culled stands, and seed physical characters, germination and seedling traits were assessed. Seed weight, seed thickness and percentage germination increased by 32.1%, 4.43% and 22.37%, respectively in the culled stand compared to the non-culled stand. Culling also increased the speed of germination, seedling dry weight and seedling vigor index. Heritability values were high for seed weight (0.974) and seed thickness (0.948) while medium values were observed for percentage germination (0.577) and total dry weight (0.534). Predicted genetic gain was 11.13% and 11.22% for seed weight and percentage germination, respectively. The actual gain was 32.1, 51.9 and 22.9% for seed weight, percentage germination and total dry matter, respectively. In conclusion, SPAs established by culling inferior trees could serve as sources of good quality seeds for reforestation programs until genetically improved seeds are made available.

An Assessment of Financial Viability of Big Onion Seed Production in Matale District

Unavailability of good quality seeds of recommended big onion varieties is a major constraint for increasing the productivity of big onion cultivation in Sri Lanka. The purpose of this study was to investigate the financial feasibility of big onion production using domestically produced true seeds at farmer level. The specific objectives of the study were to compare big onion yields obtained using local and imported true seeds, compare the financial viability of big onion production using local and imported true seeds and to assess the financial viability of local true seed production in Matale district. A production function was estimated to achieve the first objective and cost benefit analysis was conducted to achieve the second and third objectives. Primary data were collected from 144 big onion farmers and 74 big onion seed farmers in Matale district. The production function estimates showed that the yield with local true seeds was 1.32 times higher than that obtained from imported true seeds. The profitability of big onion cultivation with local true seeds and imported true seeds were Rs. 27.69 and 12.95 per kg, respectively, in Yala 2009. The profitability of local true seed production was Rs. 4,497 per kg in Maha 2008/09. These results indicate that true seed production is financially feasible at farmer level and commercial big onion production using local true seed is more financially attractive when compared to that of imported true seeds. <br /><br /><strong>Key words:</strong> Big onion seeds; Cost benefit analysis; Financial viability. <br /><br />DOI: 10.4038/tar.v22i1.2675<br /><br /><em>Tropical Agricultural Research</em> Vol. 22 (1): 107-112 (2010)<br /><br />

Teste de condutividade elétrica para sementes de feijão-mungo-verde

A utilização de sementes de boa qualidade é fundamental para o estabelecimento adequado de uma lavoura. Para uma análise mais precisa da qualidade de sementes, faz-se necessário complementar as informações fornecidas pelo teste de germinação com testes de vigor, possibilitando, assim, selecionar os melhores lotes para comercialização e semeadura. Dentre esses testes, destaca-se o de condutividade elétrica. Objetivou-se neste trabalho estabelecer uma metodologia adequada para o teste de condutividade elétrica em sementes de feijão-mungo-verde, considerando períodos de embebição e número de sementes. Foram utilizados seis lotes de sementes e o teste de condutividade elétrica foi realizado com as seguintes variações: 100, 75 e 50 sementes embebidas em 75 mL de água destilada a 25 °C, com leituras realizadas após 3, 6, 9, 12, e 15 horas de embebição. O teste de condutividade elétrica conduzido com quatro sub-amostras de 50 sementes embebidas em 75 mL de água destilada permite a separação dos lotes a partir de 3 horas de embebição, mostrando-se promissor na avaliação da qualidade das sementes de feijão-mungo-verde.

Increase of Farmers' Knowledge through Farmer Seed Production Schools in Vietnam as Assessed on the Basis of Ex-ante and Ex-post Tests

The study was designed to assess changes in farmers' knowledge of farmer seed production through schools (FSPSs) in Vietnam. A set of 25 questions covering five technical areas of the seed production process was used for pre and post knowledge testing at 12 FSPSs in the provinces Binh Dinh, Nam Dinh, Nghe An and Dong Thap. The main findings show an overall increase in farmer's knowledge scores after attending the FSPS. FSPS-farmers with low scores on the pre-field school test (ex-ante) scored much better on the post field school test. Gender had no effect on the test scores. Binh Dinh province had significantly higher mean scores on the post field (ex-post) school test compared to farmers in Nam Dinh, Nghe An and Dong Thap provinces. The increase in knowledge score is linked to the application of good practices learned in the field school as farmers who applied good quality seeds, low seed rates and the transplanting method showed a large increase in scores. The results of this study indicate that the tests provide insight into the knowledge gaps.

Opportunities and major constraints in Agroforestry systems of Western U.P: A vital role of Star Paper Mills, Saharanpur (UP) -India

Star Paper Mills is among the 15 largest virgin fibers paper mills in India. It has a good rapport in National and International market and has a long history of more than 70 years (since 1938). The industry is engaged not only in making of different kinds of papers e.g. Virgin fibre paper, cultural papers etc. using wood pulp as raw material from Eucalyptus, Bamboo, Poplar and other fibrous species but also engaged in implementing and promoting agroforestry and social forestry programme on large scale in different districts of Western Uttar Pradesh (India). Under its agroforestry programme around 3 crores seedlings were raised and distributed among the farmers. Star Paper Mills also provides good quality seeds of Eucalyptus and Bamboo, pesticides, micronutrients, manual of guidance etc. free of cost to the farmers for developing Kisan nurseries. 224 nurseries have been developed and 43.7 million seedlings distributed amongst farmers during 2008-2009 in adjoining districts. We have thus contributed to green an area of around 68688 ha. Now our programme envisages raising of 40 million seedlings every year through Kisan Nurseries. Star has also successfully developed infrastructure to develop superior clones of Eucalyptus and Poplar of high yield and their propagation technology on commercial scale through vegetative means of propagation under standardized mist chamber condition. Around 18 lac clonal plants of Eucalyptus were supplied to the farmers annually. Clonal plantation which yield double the productivity compared to seedlings in shorter period is proving a boon to the farmers of Western Uttar Pradesh. Programme has been receiving encouraging response from the farmers who mostly raise Eucalyptus and Poplar on the boundaries of their farm land. The programme was initiated since last 6 years back and operating successfully. As regards marketing, the demand of wood based industries e.g. Paper Mills, Ply wood and Board Industries in particular is increasing rapidly and the production of wood is not able to cop-up with the growing demand of wood as wood is the prime raw material of such industries for the making of different wood based products. For this the farmers of Western Uttar Pradesh are consequently benefited from competition among various industries for raw material. Marketing is not a problem for the farmers to sale their crop at the time of harvesting. Farmers are however confronting with many problems like No system for proper evaluation of their crop and they are completely in the hands of middle man. They are also facing under estimated price of their crop due to different levies laws e.g. Transit fee and Mandi fee. In addition to payment, farmers have to face hardship in procuring the passes from these departments. Beside this there is an apprehension of invasion of any disease in epidemic from like Gall. There is considerable damage in South India by this Wasp. We should take remedial and preventive measures. Now the research work is fully focused on to find out certain preventive and remedial measures to over come this problem.

Seed maturity indices for four multipurpose forest tree species of India

The study was carried out to develop maturity indices for seeds of four important multipurpose tree species in North India viz. Acacia catechu Willd., Acacia nilotica Willd., Albizia lebbeck Benth., and Tectona grandis L. We suggest that a composite seed harvest index that combines several fruit and seed parameters may be a useful in predicting better seed germination in the species studied. Thus, for achieving maximum seed quality, seeds of A. catechu should be harvested during the second week of January when the seed and pod moisture is 20-23%, 100-pod weight is approximately 23 g, and the seed colour changes from greenish-brown to light brown. The best period for harvesting good quality seeds of A. nilotica is the second fortnight of June when the pod and seed moisture is 5-6% and 100-pod weight is approximately 6 g. A. lebbeck pods should be collected during the last week of February when the seed and pod moisture is approximately 10%, 100-pod weight is approximately 10 g, the pods have not yet started to split, and the seed colour changes from light brown to dark brown. In T. grandis the suitable period for fruit harvest is the first fortnight of March when the 100-fruit weight is between 35-40 gm, the fruit moisture is approximately 14%, and the fruits become lighter in colour.

The commodity systems of four indigenous leafy vegetables in Senegal&lt;sup&gt;#&lt;/sup&gt;

Increasing the production of traditional leafy vegetables that are well adapted to the agro-ecology of Senegal, easy to grow and requiring low inputs, could greatly help to solve the poverty and malnutrition problems in Senegal. However, leafy vegetables are often overlooked by the scientific community. The species of leafy vegetables dealt with in this paper are roselle (Hibiscus sabdariffa L.), cowpea (Vigna unguiculata (L.) Walp), amaranths (Amaranthus L. spp.) and Moringa (Moringa oleifera Lam). To increase production of traditional leafy vegetables, access to good quality seeds is necessary. Two plantcollecting missions were undertaken throughout Senegal by a multidisciplinary research team. Experimentation on Hibiscusregeneration and characterisation was conducted at ISRA-CDH research station. Sixty-four accessions were collected amongthe four species. Forty-eight accessions of roselle (Hibiscus sabdariffa L.) were characterised. The level of dissimilarity (63%) within the accessions of roselle confirmed the high degree of intra-species variability. The Richness Index determined for the Diaobe and Matam markets indicated a high degree of genetic diversity of roselle. These are used to select three new lines according to farmers’ preference criteria. In addition, socio-economic surveys were conducted in two pilot villages. It was found that planting dates for leafy vegetablesvaried greatly, depending on species, locality and season. Sowing was mainly done broadcast. Organic fertilisers were commonly applied. Eighty per cent (80%) of the farmers applied an NPK formulation and small quantities of urea. Traditional irrigation methods are often used in the growing of traditional leafy vegetables. The seeds used by farmers were a mixture of varieties. Farmers identified four types of each of roselle, amaranth and cowpea, but could not differentiate any variety forMoringa. Local markets constitute the main roselle seed supply source. Few farmers have developed traditional methods of seed conservation. Selling of seed is not a common activity in rural areas. Generally, farmers exchange gratuitously theirs seeds. Leaves are commonly sold at the field, in the village, in the nearest city and weekly at local markets called ’Louma‘. Average annual income generated by leaves varies from 41 to 500 USD. Leafy vegetables are used as food and for medicinal purposes. Leafy vegetable consumption in Senegal is around 23 g/person·d.

Crystal Growth of DAST

We explore the growth of the highly nonlinear optical trans-4′-(dimethylamino)-N-methyl-4-stilbazolium tosylate) (DAST) crystals from methanol solutions. We determined the key thermodynamic quantities of the DAST/methanol system, which allowed us to optimize the conditions of the crystal growth and to manipulate the size and morphology of the obtained crystals. We developed confined spontaneous nucleation (CSN), a new technique to control the nucleation and produce good quality seeds and platelets for nonlinear optical applications such as the generation of THz waves. We propose the total excess of Gibbs free energy per volume of the solution as a new parameter (ΔG/Vsol) that fundamentally affects the growth rate from solution instead of the commonly used supersaturation. This parameter involves also concentration and temperature dependence and is therefore applicable to a large range of growth conditions. A model for the growth dynamics of DAST crystals based on the mass balance equations and the measure...

Participatory sunflower production, technology dissemination and value addition in Southwest Kenya

Sunflower is widely adapted and one of the major oil crops grown in Southwest Kenya. It is regarded as a high value cash crop and a source of high qualityedible vegetable oil in Kenya. Southwest Kenya lies within the Lake Victoria region and is suitable for sunflower production. During Participatory Rural Appraisals (PRAs) farmers attributed the low production to poor agronomic practices, inadequate pest and disease control, lack of high yielding varieties, decline in soil fertility, shortage of good quality seeds at planting, low producer prices, shortage of sunflower seed for processing, lack of access to credit, lack of markets and market information, weak research - extension – farmer linkages and low adoption of developed technologies. To address some of these constraints, on-farm research activities were undertaken by Kenya agricultural Research Institute (KARI) using participatory research approach targeting small-scale resource challenged farmers who are vulnerable to food and nutritional insecurity. The PRA was favoured because the top-down approach of technology development and dissemination had led to poor adoption of technologies. The objectives of the project were; to scale up promising sunflower varieties, enhance value addition activities and to link farmer marketing groups to existing and new market opportunities. The treatments were; intra – row planting, pure stands (75 x 30 cm and 70 x 30 cm), alternate planting (1 row sunflower and 1 row maize) and two rows sunflower and two rows maize. The results indicate that pure stands had significantly (P ≤ 0.05) higher yields of both seed and oil than other treatments. However during farmer evaluation single alternate (1 row sunflower with 1 row maize) was ranked first followed by pure stand (75 x 30 cm) and intra row in a decreasing order. The single alternate row was ranked first based on food security, bird control and income generation since it provides both maize for household use and sunflower as a cash crop. Therefore this technology should be recommended for up scaling to more farmers in the region. Key words: Sunflower, PRA, scaling up, value addition.

Seed production and seedling survival in a 50-year-old stand of Corsican pine (Pinus nigra subsp. laricio) in southern Britain

Summary There is much literature on natural regeneration which emphasizes the importance of good seed year, but few authors consider seed input in terms of the combination of seed quantity (i.e. number of seeds) plus seed quality (i.e. percentage of viable seeds). We have considered both aspects and also attempted to identify the proportions of good vs poor quality seeds contributing to natural regeneration via ‘ seed rain ’ vs ‘ cone drop ’ . In addition to studying seed input, we looked at the effects of vegetation control, ground preparation and protection from small mammals on seedling emergence and survival. Over a 3-year period (February 2001 to March 2004), there was enough seed production and seedling survival to conclude that natural regeneration could be successful beneath a 50-year-old stand of Corsican pine in the south of England. Peaks of pine seed release occurred in March/April in 2002 and 2003, but it was extremely surprising to observe that some seed was trapped in virtually every month of the 3-year study, demonstrating an almost continual release of (at least) small quantities of seeds. In line with this fi nding, although most pine seedlings were found shortly after peak seed dispersal in May, June and July; new seedlings were found in every month throughout the study except February and October. In general, vegetation control and ground preparation had a positive effect on seedling survival; the probability of a seedling surviving for 300 days was between 50 and 60 per cent.

Germinated Oil Palm (Elaeis guineensis) Seeds: Process Innovations to Improve Seed Quality and Performance of Nursery Plants

The quality of germinated oil palm seeds and nursery practices at planting affected emergence and plant vigour. ASD of Costa Rica has implemented several innovations to the seed germination process which have increased the proportion of germinated seeds that give rise to better quality plants in the prenursery phase. A special machine was designed that mechanically separates the mesocarp from the seed while reducing the amount of fibres that remain adhered to the seed shell to a minimum, and avoiding that these fibres become a substrate for storage fungi that may affect germination. More recently, another machine was developed that works on fresh bunches arriving from the field, and mechanically separates the fruits with spikelets facilitating the subsequent separation of the individual fruits. This process is very fast and reduces mechanical damage to the seeds to a minimum when compared with manual separation of spikelets using an axe. Another important advancement has been the substitution of plastic bags for semi-hermetic plastic containers to keep the seeds during storage and heat treatment to break dormancy. This resulted in better control of seed moisture that allowed faster and more uniform germination with subsequent improved plantlet quality. More recently, ASD implemented the use of a “film coating” to identify its seed varieties with different colours and at the same time improve fungal control by mixing the polymer with a fungicide. Research on factors that affected seed quality was focused on how fast the seeds germinate after breaking dormancy and the effect of storage fungi. The impact of planting poor quality seeds on plant vigour was investigated as well. It was found that the percentage of emergence after sowing and the number of good quality plantlets were inversely proportional to the time required for breaking dormancy. Seeds with signs of contamination by storage fungi (such as Penicillium sp.), or with an abnormal germination (abnormal radicle or plumule) did not germinate or give rise to abnormal plants. All these factors are seriously considered during selection of commercial hybrid seeds. The use of premium quality germinated seeds assured the establishment of good nurseries, but did not prevent losses due to poor management. Some good quality seeds did not germinate or gave rise to poor plants when planted in an inadequate substrate (clayish and water saturated soils) or without shade early after sowing. Keywords: Oil palm, seed germination, seed quality.

Effect of Seed Quality and Combination Fungicide-Trichoderma spp. Seed Treatments on Pre- and Postemergence Damping-Off in Cotton

ABSTRACT Good quality seeds of cotton cultivars often escaped pre-emergence damping-off incited by Pythium spp. and Rhizopus oryzae, and they were resistant to postemergence damping-off incited by Rhizoctonia solani. Poor quality seeds, however, were highly susceptible to both phases of seedling disease and required seed treatment in order to survive. Pre-emergence damping-off incited by Pythium spp. and Rhizopus oryzae could be controlled by seed treatment with biocontrol preparations of a number of Trichoderma spp., but these treatments were much less effective in controlling postemergence disease incited by Rhizoctonia solani. Postemergence seedling disease can be controlled by fungicides, but they were much less effective in controlling the pre-emergence phase of the disease. Combination seed treatments of poor quality cotton seeds with fungicides and Trichoderma spp. preparations, followed by planting in pathogen-infested soil, indicated that this technique will control both phases of seedling disease. Seed treatment with either the fungicides or the biocontrol agents alone did not achieve this goal. The optimum combination treatment for disease control was that of chloroneb plus Trichoderma spp., followed by chloroneb plus metalaxyl (Deltacoat AD) plus T. virens strain G-6.

Abnormal spindle orientation during microsporogenesis in an interspecific Brachiaria (Gramineae) hybrid

This paper reports a case of abnormal spindle orientation during microsporogenesis in an interspecific hybrid of the tropical grass Brachiaria. In the affected plant, prophase I was normal. In metaphase I, bivalents were regularly co-oriented but distantly positioned and spread over the equatorial plate. In anaphase I, chromosomes failed to converge into focused poles due to parallel spindle fibers. As a consequence, in telophase I, an elongated nucleus or several micronuclei were observed in each pole. In the second division, the behavior was the same, leading to polyads with several micronuclei. A total of 40% of meiotic products were affected. The use of this hybrid in production systems needing good-quality seeds is discussed.

The Effect of Individual Selection for Genetic Diversity of Acacia mangium Seedling Seed Orchard Using Aflp Markers

Establishment of seed orchard is aimed at producing good quality seeds which is an important activity for breeding program. Seed orchard is also a base population, thus its genetic diversity is depending on its design and composition (provenance, family and individual tree). Selection of an individual tree in seed orchard is needed for the enhancement of retaining good-character trees. However, selection of individual tree can change the genetic diversity of seed orchard, and the degrees to which the genetic diversity will change depend on the used selection methods. In order to investigate the effects of selection methods, 4 simulations of selection methods based on height, diameter and stem performance of individual trees were used. The differences among the 4 methods were the ranking of individual trees those selected, and families and provenances those have been represented. Seedling seed orchard of Acacia mangium in Wonogiri, Central Java was used as materials. Analysis of genetic diversity was carried out using AFLP markers. Nine primer combinations were used to produce 1025 AFLP banding patterns. Among those banding patterns, only 109 were polymorphic markers. No significant effect of individual tree selection was revealed in this study. Even though the selection was done intensively, only 7.1% of genetic diversity was reduced. In other words, the selection activity did not reduce the genetic diversity of seed orchard significantly. The result is important for developing future tree improvement of A. mangium , including development of hybrid between A. mangium and A. auriculiformis .