Alfred Opiyo
Certified Expert
FARM BOOKSHOP
SEED QUALITY.
A seed is very important input in crop production enterprise regardless to the purpose for which one is doing the farming whether for commercial or subsistence reasons. Seeds are the foundation of agriculture despite the modernization in a day -to-day farming operation, but without consistent supply of best quality seeds ,crop yields and crop quality will be greatly compromised.
Seeds being the genesis of a new crop generation and of course a continuation from the previous generation as well therefore before settling on variety or cultivar to plant, the farmer ought to consider looking at various aspects of seed quality parameters for all these contribute to a larger extent the level of your success in agronomic and horticultural crops.
How is seed quality determined? Seed quality can be measured subject to the following parameters. Germination percentage, seed purity, germination vigor, seed uniformity and viability.
Germination percentage in simple language this parameter can be cross checked by the farmer /grower before planting or sowing the seed even though it is usually given on the packaging material for most certified seeds if not all sold out there, but it is prudent for on the farm test because germination percentage is likely to deviate due to constant changes in environmental factors. Germination percentage refer to the number of seeds that are able to germinate out of a constant number planted then translated to percentage under conducive germination/growing conditions(enough moisture,required warmth,oxygen supply, enough light and growing media) within specified time frame.Example 10 seeds of maize planted, 8 of 10 germinated with in 5-7 days can be said to have 80% germination percentage. Why time factor? Different plants seeds have variable seed dormancy hence germinate after different number of days after planting however seeds from same plant should germinate within the same time frame. Any germination less than 70% is considered low and may call for increased seed rate to ensure correct plant population which is an important factor for better yield.
Seed purity This parameter entails the physical and genetic purity which affects physiological soundness and health status of the seed. Physical purity seeds should be free from foreign materials e.g seeds of other plants,noxious weeds, inert materials diseased materials or pests/insect damaged seeds. This quality if not checked is likely to affect the planting value of the seed and consequently final yield to achieve physical purity,proper cleaning sorting and grading after collection and before sowing/storage is advised. Genetic purity encompasses seed being true to type which can be explained as the seedling/plant or tree obtained from the germinated seeds bears the expected traits/ characteristics of the mother plant e.g bearing the transferable traits like disease tolerance, drought tolerance/resistance.
Seed vigour this refer to the sum total of performance and developmental activities that arise from germinating and young growing seedling in a stressful growing condition, a physical check can be made on roots,shoots in respect to level of development subject to measured time frame. Not all seeds planted under same factors behave in a similar way or develop at the same rate
Seed viability this is the ability for the living organism, embryo to germinate. Seed viability affects germination percentage. Factors that affects viability include; physical damages due to breakages,pests attack, pathogen/disease causing organisms attack, storage factors seeds stored in poor conditions e.g moist conditions causing seeds to rot or subjected excessive temperatures in stores or during drying process that might have denatured /killed the embryo
Seed uniformity this refers to the seed possessing good shape, size colour and weight. Under sized dis-coloured ,malformed shapes and underweight seeds definitely affect the embryo,a living organism
embedded on the food storage tissue therefore can compromise germinability and seedling vigour
**
Prepared by:
Alfred Opiyo
Agriculture trainer
Ugenya technical and vocational college
Department of agriculture and food science
SEED QUALITY.
A seed is very important input in crop production enterprise regardless to the purpose for which one is doing the farming whether for commercial or subsistence reasons. Seeds are the foundation of agriculture despite the modernization in a day -to-day farming operation, but without consistent supply of best quality seeds ,crop yields and crop quality will be greatly compromised.
Seeds being the genesis of a new crop generation and of course a continuation from the previous generation as well therefore before settling on variety or cultivar to plant, the farmer ought to consider looking at various aspects of seed quality parameters for all these contribute to a larger extent the level of your success in agronomic and horticultural crops.
How is seed quality determined? Seed quality can be measured subject to the following parameters. Germination percentage, seed purity, germination vigor, seed uniformity and viability.
Germination percentage in simple language this parameter can be cross checked by the farmer /grower before planting or sowing the seed even though it is usually given on the packaging material for most certified seeds if not all sold out there, but it is prudent for on the farm test because germination percentage is likely to deviate due to constant changes in environmental factors. Germination percentage refer to the number of seeds that are able to germinate out of a constant number planted then translated to percentage under conducive germination/growing conditions(enough moisture,required warmth,oxygen supply, enough light and growing media) within specified time frame.Example 10 seeds of maize planted, 8 of 10 germinated with in 5-7 days can be said to have 80% germination percentage. Why time factor? Different plants seeds have variable seed dormancy hence germinate after different number of days after planting however seeds from same plant should germinate within the same time frame. Any germination less than 70% is considered low and may call for increased seed rate to ensure correct plant population which is an important factor for better yield.
Seed purity This parameter entails the physical and genetic purity which affects physiological soundness and health status of the seed. Physical purity seeds should be free from foreign materials e.g seeds of other plants,noxious weeds, inert materials diseased materials or pests/insect damaged seeds. This quality if not checked is likely to affect the planting value of the seed and consequently final yield to achieve physical purity,proper cleaning sorting and grading after collection and before sowing/storage is advised. Genetic purity encompasses seed being true to type which can be explained as the seedling/plant or tree obtained from the germinated seeds bears the expected traits/ characteristics of the mother plant e.g bearing the transferable traits like disease tolerance, drought tolerance/resistance.
Seed vigour this refer to the sum total of performance and developmental activities that arise from germinating and young growing seedling in a stressful growing condition, a physical check can be made on roots,shoots in respect to level of development subject to measured time frame. Not all seeds planted under same factors behave in a similar way or develop at the same rate
Seed viability this is the ability for the living organism, embryo to germinate. Seed viability affects germination percentage. Factors that affects viability include; physical damages due to breakages,pests attack, pathogen/disease causing organisms attack, storage factors seeds stored in poor conditions e.g moist conditions causing seeds to rot or subjected excessive temperatures in stores or during drying process that might have denatured /killed the embryo
Seed uniformity this refers to the seed possessing good shape, size colour and weight. Under sized dis-coloured ,malformed shapes and underweight seeds definitely affect the embryo,a living organism
embedded on the food storage tissue therefore can compromise germinability and seedling vigour
**
Prepared by:
Alfred Opiyo
Agriculture trainer
Ugenya technical and vocational college
Department of agriculture and food science