Добірка наукової літератури з теми "Certified seedling"

Mango is a favorite tropical fruit in both domestic and international markets. Due to its features that are relatively easy to grow and more resistant to pests and diseases, the success rate of producing the seedlings is higher compared to the other perennial fruit plants. Despite of these advantages, the sector is still facing several constrains. One of them is the low rate of certified seedling used that may affects the productivity of mango trees. Limited availability of superior certified mango seedlings that is faced by mango nurseries is suspected as one of the cause. This paper aims to describe the dynamic that occurs in mango nursery sector in one of mango production centres in West Java. The data was collected through survey of 260 nurseries in 2016 and was part of Indohort project research; a collaboration between Australian Centre for International Agricultural Research (ACIAR), Iindonesian Center for Horticulture Research and Development (ICHORD), and the University of Adelaide. The results showed that: (1) Only 7% of the total number of nurseries has a formal certification for seedlings that are produced, (2) in average, mango nurseries produce less mango seedlings in 2016 compared to 2011; (3) mango nursery’s specialization rate decreased from 32% in 2011 to 19% in 2016, (4) the share of Harumanis (mango variety that is most preferred in Indonesia) seedlings production per nursery, decreased from 89% in 2011 to 65% in 2016; (4) Further improvement related to mango seedlings marketting chain needs to be done to create a better mango seedling market structure along the chain.

Abstract The objective of this study was to study the seed quality aspects of wheat (Triticum aestivum L.) and the extent of weed seed contamination present in wheat seeds produced in different regions of Iran. Four districts (cities), each including 12 fields (six certified seed fields and six farm-saved seed fields), were selected in each regions (provinces). One kilogram of the wheat seed sample was collected from each field for analysis in the laboratory. Wheat seeding was commonly done by farm-saved seed sourced from within the farm due to the high costs of certified seeds purchased from outside sources, followed by the low seed quality. The use of a farm-saved seed resulted in a higher germination rate and a lower mean time to germination compared with another system. The more positive temperatures experienced by mother plants could decrease the number of normal seedling and seedling length vigor index. Generally there was virtually no difference about physiological quality between certified seed and farm-saved seed sector that is related to lower quality of certified seed. The certified produced seeds had the lower number of weed seed, species and genus before and after cleaning. The highest seed purity and 1000 seed weight was obtained from the certified seed production system. The need for cleaning the farm-saved seed samples before sowing is one of the important findings of this survey.

Sugarcane bagasse is the fibrous material remaining after removing the sucrose, water, and other impurities (filter mud) from the millable sugarcane. Louisiana sugarcane mills use a portion of the sugarcane bagasse to produce steam power to run equipment within the mill and/or as a boiler fuel for the clarification, evaporation, and crystallization processes. Sugarcane bagasse ash (SBA) is a by-product of the thermal conversion of the sugarcane bagasse. The purpose of this research was to investigate the use of SBA as an amendment to soilless planting media for the production of vegetable seedlings. The SBA was combined by volume with a commercial certified organic soilless growing media into 5 combinations (0%:100%, 25%:75%, 50%:50%, 75%:25%, and 100%:0%, SBA and growing media, respectively). Bean (Phaseolus vulgaris L.) var. ‘Bowie’ and Chinese kale (Brassica alboglabra) var. ‘South Sea’ were planted in each of the 5 different planting mixtures. As the percentage of SBA increased from 0% to 100%, the bulk densities increased, 0.118 to 0.712 g/cm3, while the porosity, water saturation percentage, and water at field capacity decreased. Increasing the SBA percentage significantly impacted total exchange capacity, pH, organic matter, estimated nitrogen release, and all other nutrients measured, except for sodium. The research indicates that the addition of SBA can enhance bean and Chinese kale seedling growth depending on the percentage of the ash added to the growth media. Bean and Chinese kale harvest parameters typically peaked at 25% SBA, and then decreased with increasing SBA %. Adding 25% SBA did benefit the seedling growth by providing additional nutrients for seedling growth, while reducing the cost of production by supplementing the more expensive greenhouse media by a readily available by-product of the sugarcane industry. Increasing the SBA % to 50% or greater is not recommend. Additional research is needed to determine the percentage above 25% and below 50% SBA that would still benefit seedling plant growth.

Rice blast, caused by Pyricularia grisea, is an important and serious disease of rice (Oryza sativa) in the southeastern United States. The disease sporadically reaches epidemic proportions on susceptible cultivars within fields and over large areas within Arkansas. The main overwintering sources of inoculum reportedly include infected rice stubble, related host species, and infected seed. The objectives of the research were to (i) determine whether rice seed grown in Arkansas were infected with P. grisea, (ii) investigate the relationship between seed infection and seedling disease, and (iii) determine if planting naturally infected seed could lead to the subsequent development of rice blast on seedlings in the field. The results of seed assays showed that P. grisea was detected in samples of foundation, certified, and production seed. Estimated levels of infection by P. grisea of rice seed from 66 samples of rice seed grown in Arkansas ranged from 0 to 10.5%. Planting infected seed in the greenhouse and the field resulted in seedling infection. Planting naturally infected seed may result in disease development (i) from seedlings grown from infected seed planted beneath the soil surface, (ii) from seedlings grown from germinating seed left on the soil surface, (iii) from seed coats, or (iv) from nongerminated seed left on the soil surface after planting. Additional research is necessary to establish the mechanisms of infection of seedlings and to establish disease thresholds for this important fungal pathogen of rice.

Seed viability and vigour play important roles in seedling emergence, plant stand establishment and yield potential. The majority of cereal fields in Finland are typically sown with farm saved seed (FSS). If the quality of the seed is not known, there can be insidious yield reduction. This research was conducted to study the effects of seed quality on seedling emergence rate, seedling number and yielding capacity. The study comprised three-year field experiments conducted during 2007–2009, established at three sites: Jokioinen, Nousiainen and Ylistaro. Spring barley cultivars Saana (2007) and Annabell (2008-2009) were sown at rate of 500 germinating seeds m-2. Five seed lots were included as treatments: farm saved seed (FSS); downgraded seed 2.7 mm); upgraded seed >2.7 mm with disinfection (FSS>2.7 mm + dis); and commercial certified seed with disinfection (CCS). Up- and down-graded seed lots (FSS2.7 mm, and FSS>2.7 mm + dis) all originated from the FSS. Seedling emergence rate was measured from the time when coleoptiles started to break through the soil surface. The number of seedlings (3 × 1 m row per plot) was recorded at five-day intervals four times from the same rows. Plots were harvested at physiological maturity and grain yield (kg ha-1), hectolitre weight (HLW, kg) single grain weight (SGW, mg) and grain protein content (%) were recorded. Seed lots of CCS and FSS>2.7 mm + dis enhanced seedling emergence rate and increased the number of plants compared with other treatments. These two seed lots also produced the highest grain yield and had the lowest grain protein. Seed quality had an apparent effect on plant stand establishment and grain yield. A seed lot effect was evident despite identical targeted sowing rates that took into account germination rate and seed weight. Therefore, differences in seedling emergence and yielding capacity were likely outcomes of variation in seed vigour among the five treatments.;

The transition period to certified organic production can present a significant weed management challenge for growers. Organic certification requires that prohibited fertilizers and pesticides must not have been used for 36 mo before harvest of the first organic crop. Understanding how organic management practices and initial weed seed-bank densities affect weed population dynamics during the transition period may improve weed management efficacy and adoption of organic practices. We examined how tillage systems (full or reduced) and cover crop species planted during the first transition year (rye or a mixture of timothy and red clover) affect the seedling densities of three common annual weed species, common lambsquarters, velvetleaf, and foxtail spp., during the 3-yr transition period. Weed seeds were applied in a one-time pulse at the beginning of the study at three densities, low, medium, and high (60, 460, and 2,100 seeds m−2, respectively), and cumulative seedling densities of each species were assessed annually. Treatment factors had variable and species-specific effects on weed seedling densities. In general, the full-tillage system, with an initial cover crop of timothy and red clover, resulted in the lowest density of weed seedlings following seed-bank augmentation. There was little consistent association between the initial densities of applied weed seeds in the weed seed bank at the start of the transition and weed seedling densities at the end of the transition period. This suggests that when multiple crop and weed cultural management practices are employed during the organic transition period, initial failures in weed management may not necessarily lead to persistent and intractable annual weed species management problems following organic certification.

The purpose of this study was to study the supply of potato seed in West Java, Indonesia. The research respondent is farmers who use seed, with a sample of 377 farmers and a survey of all seed breeders totaling 43 farmers, using proportionate stratified random sampling. This research report is also complemented by a review analysis of potato seedling development in the last five years. There is considerable interest in the potential that can be developed, productive aged farmers, and adoption of new technologies. Factors exerting a strong influence include capital, technology, adequacy of seed, the proportion of certified seed, and farm credit. Factors identified as influencing the level of demand include the proportion of certified seed, seed prices, capital, and credit allocation for potato farming; at the level of supply factors that can exert influence are the availability of seed, the selling price of seed, and the capital of breeding farmers. Policy simulation on the use of certified seed potatoes shows that increase in the number of specific farm credits, the price of seed and fixed farm capital results in increased use of certified seed and reduced self-selection of seed.

`Guardian' peach rootstock has shown improved survivability in areas where root-knot nematode and peach tree short life are a problem. Many peach rootstocks are typically propagated from seed. Availability of seed may vary and the long-term genetic uniformity of rootstock material may be difficult to maintain due to out-crossing during seed production. A reliable, successful vegetative propagation method would potentially increase the rate at which material could be made available and more closely ensure genetic uniformity. Production of liners was compared between rooted cuttings and seed of mature `Guardian', `Lovell', and `Nemaguard' peach trees. Seed were stratified under uniform conditions, planted at initial germination, and seedling emergence recorded 30 days after planting. Terminal softwood and semi-hardwood cutting were treated with KIBA and rooted under intermittent mist in a greenhouse. Rooting percentage was equal to or greater than percent seedling emergence. Optimum results were obtained with semi-hardwood cuttings taken in July and August. Rooted cuttings transplanted to the field produced liners of equal or greater quality than liners produced from seed. Seedlings exhibited variability in growth in the nursery area. Rooted cuttings had fewer lateral branches in the lower 15 cm of rootstock where trees were T-budded with certified, virus-indexed buds of `Cresthaven' peach.

This thesis examines climate-related risk behaviours among small-scale citrus farmers and their decision to adoption certified seedlings and use of agrochemical inputs in East Java, Indonesia. The analysis is important for understanding citrus farmers’ behaviours regarding climate change issues. Understanding farm households climate related behaviours is key to designing appropriate smallholder support and advisory services. Given the importance of climate change to rural agricultural communities in developing countries, governments, NGOs and international development agencies continue to make substantial efforts to improve the ability of small-scale farmers to adapt. Yet, too often, national adaptation policies and programs ignore insights from existing smallholder adaptation practices. Previous studies show that behavioural insights are critical in developing an understanding of climate risk management by farmers. An important aim of this thesis is to understanding climate-related influences on smallholders’ decisions. The research objectives are to: (i) understand the extent of perceptions of risk among small-scale citrus farmers related to a range of climate change events and to identify the drivers of their risk perception at aggregated and disaggregated levels; (ii) provide analytical insights into the adoption of certified citrus seedlings by small-scale farmers by analysing the extent to which they value the certification of citrus seedlings and the role of this factor in influencing the adoption of higher-yielding, climate-risk resilient and disease-free citrus varieties; and (iii) explore the extent of use of chemical inputs and the role of risk preferences, intrahousehold dynamics and social networks on the household expenditure spent on chemical inputs. The research uses data from a household survey of 500 citrus farmers with interviews of both the male and female household heads. The first research objective was analysed by employing seemingly unrelated regression models (SUR) and ordered logistic regression models (OLM), the second objective was estimated using a multinomial logit model, and the third objective employed joint modelling of risk, intrahousehold dynamics and spatial factors in a spatial regression model. Among the key contributions of this thesis is integrating the research on complex patterns of risk behaviours, from both the economics and psychology literatures, into climate research on risk perceptions through a straight-forward extension of current approaches to the analysis of the risk perception index. An important result is the disadvantage of using only the aggregate approach in analysing risk perception because it could underestimate and simplify the complex representation of climate risk behaviours. This study also presents empirical support for the use of information and communication technology based extension as an efficient extension tool to reach more farmers than in traditional methods. A second result highlights how farmers' beliefs about the yield and production risks of particular seedling types, along with risk preferences, were significantly related to farmers’ intentions to adopt particular seedling types. This study also found the relationship between climate-related variables (i.e. climate information source and climate extension) and farmers’ decisions to use certified seedlings. Lastly, this thesis finds that more risk-averse households tend to have lower spending on insecticides and the use of this input is also significantly associated with higher profit variability. A wife’s leadership could lead to a considerably lower expenditure for fungicides, but higher herbicide expenses; and a higher disagreement between spouses is associated with more insecticides and fungicides costs. The pattern of chemical inputs usage is spatially dependent on endogenous effects, while spatial disturbance effect existed for the use of chemical fertilisers and herbicides.
Thesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food & Wine, 2020

AbstractThe availability of clean planting materials and functional seed regulatory systems is indispensable for fostering a sustainable seed yam system. The Yam Improvement for Income and Food Security in West Africa (YIIFSWA) project of the International Institute of Tropical Agriculture (IITA) developed the capacity of National Agricultural Research Institutes (NARIs) in their use of standardized Temporary Immersion Bioreactor (TIB) and Vivipak (VP) systems for high-ratio propagation and post-flask handling of yam breeder seed plantlets. Foundation seed was enhanced by supporting five private seed companies in Nigeria and three in Ghana. They were equipped with aeroponic and hydroponic technologies for foundation seed tuber production using single-node vine seedlings. For certified seed, seed yam out-growers were trained in good agronomic practices and entrepreneurship for certified seed tuber production using the adaptive yam minisett technique (AYMT). New certification standards were established for various classes of seed produced using different propagation methods and quality assurance procedures in Ghana and Nigeria. The capacity of the national regulatory organizations in both countries was enhanced to implement seed quality control and certification. Increased public sensitization and advocacy were done to raise awareness among relevant stakeholders to enhance the uptake of the seed propagation technologies and ensure a smooth interaction between the public and private sectors. This chapter summarizes the accomplishments of YIIFSWA in Ghana and Nigeria and the spillover impact on the yam belt of West Africa and beyond. The key lessons could inform the design and implementation of more effective seed projects, especially for vegetatively propagated crops.