Cultivation method for revitalized potato material in the system of original seed production

To arrange a system of virus-free potato seed production in the Sakhalin region, a series of studies undertaken to come up with a method towards potato material cultivation in film-gauze greenhouses. At the initial stage, the key agrotechnical methods were developed for growing test-tube microplants, including optimal planting plans – 70×15 cm (the highest yield derived from a standard mini-tuber fraction pcs/m2), 70×30 cm (for clone selection); spraying with insecticides (Aktellik – 3 l/ha, Rogor – 2 l/ha) and fungicides (Ridomil – 1 kg/ha, Tsineb – 2.4 kg/ha) to combat agents transmitting viral and fungal infections; chlorocholine chloride treatment (1.1%) to reduce the growth of the vegetative mass; serological analysis of plants for latent infection with viruses X, Y, S, M, F; burning tops with Reglon (2 l/ha) 2 weeks before harvesting. A set of agrotechnical methods used for producing healthy seed tubers on the Timiryazevskoye seed farm made it possible to reduce the elite cultivation cycle from 5 to 4 years, increase the yield by 57.2%, and reduce the production cost by 43.5%. Subsequently, the methods worked out for producing potato seeds were improved based on modern breeding varieties and phytoregulators (Azolen, Elena, Extrasol, Epin-Extra, Zircon) in spray mixtures with the fungicide Shirlan, contributing to an increased yield up to 34% and efficiency of a standard seed fraction up to 33%. Under production conditions, this method provided a conditionally net income of 450-700 thousand rubles/ha.

Cassava mosaic disease and its management in Southeast Asia

Key message Status of the current outbreak of cassava mosaic disease (CMD) in Southeast Asia was reviewed. Healthy cassava seed production and dissemination systems have been established in Vietnam and Cambodia, along with integrated disease and pest management systems, to combat the outbreak. Abstract Cassava (Manihot esculenta Crantz) is one of the most important edible crops in tropical and subtropical regions. Recently, invasive insect pests and diseases have resulted in serious losses to cassava in Southeast Asia. In this review we discuss the current outbreak of cassava mosaic disease (CMD) caused by the Sri Lankan cassava mosaic virus (SLCMV) in Southeast Asia, and summarize similarities between SLCMV and other cassava mosaic begomoviruses. A SATREPS (Science and Technology Research Partnership for Sustainable Development) project “Development and dissemination of sustainable production systems based on invasive pest management of cassava in Vietnam, Cambodia and Thailand”, was launched in 2016, which has been funded by The Japan International Cooperation Agency (JICA) and The Japan Science and Technology Agency (JST), Japan. The objectives of SATREPS were to establish healthy seed production and dissemination systems for cassava in south Vietnam and Cambodia, and to develop management systems for plant diseases and insect pests of cassava. To achieve these goals, model systems of healthy seed production in Vietnam and Cambodia have been developed incorporating CMD-resistant planting materials through international networks with The International Center for Tropical Agriculture (CIAT) and The International Institute of Tropical Agriculture (IITA).

Some ways for obtaining healthy potato seed material

Some methods of obtaining a healthy seed material of potatoes (meristem culture, from seedlings of leaf tubers, etc.) are considered. The possibility of obtaining in one season, in conditions of heifers, tubers from seedlings and from them leafy minitubers is shown. The data on the yield of potatoes after different methods of improving the seed material are given.

MOISTURE CONTENT AND VARIETY OF JUTE SEED IS AFFECTED BY LONG TERM SEED STORAGE

Seed perform a vital role in agricultural sector for crop production as well as seed business. Scarcity of healthy seed hinder not only the crop production but also the quality of seed. Storing of healthy seed with proper storing condition is one of the suitable methods to maximize production however, healthy seed also lose its quality during seed storage. Seed remains viable for long time if the seed stored by maintaining seed moisture content, storage temperature with storage container. So, this experiment was carried out to observe the quality parameters of jute seed during long term storing. To find out the storage effect an experiment was conducted on march, 2020 at seed laboratory, Jute Agriculture Experimental Station, Jagir, Manikganj, Bangladesh during the period of January 2016 to March, 2020. Plastic pot was used in this experiment as a storage container to store jute seeds. Three tossa jute (C. olitorius L.) varieties viz., O-795 (V1), O-9897 (V2) and OM-1 (V3) were used in this study. Result revealed that storage period and jute variety showed significant effect on different seed quality parameters. The highest seed germination, field emergence, seed vigour and the lowest 1000-seed weight, moisture content were recorded in T5 (2019-20) treatment. On the other hand, the lowest seed germination, field emergence, seed vigour and the highest 1000-seed weight, moisture content were recorded in T1 (2015-2016) treatment. Furthermore, seed germination, field emergence, seed vigour was negatively but 1000-seed weight was positively correlate with moisture content. Results revealed that extended storage period caused the decreasing seed quality and seed can be stored for three years in plastic container without hampering the seed quality.

Effect of gamma ray irradiated pollen technique on seed development pattern in Citrus

In modern fruit breeding, to reduce the breeding cycle, induction of haploid plants through irradiated pollen technique is of paramount importance. However, the major drawback is the sensitivity of pollen to higher irradiation doses as it induces abnormality in double fertilization process. Hence, optimization of irradiation doses for maximum recovery of healthy seed is very important. Present work analyzed the seed developmental pattern of Citrus grandis, pollinated with gamma irradiated pollen (100-500 Gy) of C. limon, C. limetta, and C. sinensis. Not a single fruit was retained on the tree till maturity in C. grandis × C. limon crosses; however, in other two cross combinations, fruits were harvested at maturity only up to 300 Gy irradiation doses. Among the harvested fruit, normal seed decreased gradually with increasing irradiation doses and less than 5 normal seeds per fruit were obtained at 300 Gy with maximum in C. grandis × C. limetta cross. However, abnormal and empty number no. of seeds has increased significantly with increasing irradiation doses. Developmental pattern of embryo and endosperm within normal seeds was also influenced significantly by irradiation treatment. At higher doses, seeds number with both embryo and endosperm was decreased gradually and at 300 Gy, it was reduced to 59.47% as compared to control.

Seed health of stored lentil collected from major lentil growing areas of Bangladesh

An experiment was conducted in the Plant Pathology Laboratory, Regional Agricultural Research Station, BARI, Jashore using 126 lentil seed samples collected from farmer’s store of different lentil growing areas of Bangladesh to determine physical status and fungal association with lentil seeds. The collected seeds contained different varieties and locations. The seeds were grouped into four grades according to physical status. Among the varieties the maximum apparently healthy seed i. e. grade-1 was found in BARI Masur-7 (90.92 %) and the minimum was in local (59.34 %) varieties. In respect of location the maximum grade-1 seed was recorded from Madaripur (90.75 %) and minimum in Kushtia (47.67 %) district. Germination percentage was the highest in BARI Masur-7 (94.00 %) and the lowest in BARI Masur-3 (75.42 %) variety. Among districts, the highest germination was found in seeds of Meherpur (89.83 %) and the lowest in Narail (62.97 %). A linear positive relation was found between percent germination and apparently healthy seed in case of both varieties and locations. Six fungal genera were associated with lentil seed samples viz. Fusarium sp., Alternaria sp., Stemphylium sp., Curvularia sp., Penicillium sp. and Aspergillus spp. Aspergillus niger caused highest infection (17.58 %) followed by Fusarium oxysporum, Alternaria tennuis, Stemphylium botryosum, Curvularia lunata, Penecillium sp., Aspergillus flavus, Aspergillus paraciticus and Aspergillus candidus and the lowest (4.67 %) by Aspergillus ocraceous. Average association of fungi was the highest in local variety (3.27 %) and it was the lowest in BARI Masur-7 (0.50 %). Bangladesh J. Agril. Res. 44(1): 59-68, March 2019