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 Essay - nov/dec 2004
Improving and enhancing seed performance
James C. Delouche
Professor Emeritus Mississippi State University
One of the fundamental precepts of seed science and technology is that high quality seeds perform better than those that are of lesser quality. The main implication of this precept is that improving the performance of seeds in crop production is best achieved by concentration on the development and production of high quality seeds and the maintenance of high quality through conditioning, storage, marketing and planting. No one can argue with this approach. It is effective and efficient, but is it the only approach to improve the performance of seeds? There are several other relevant questions. Are seed performance and quality essentially the same attribute? Can the performance of high quality seeds be improved without any significant change in their quality status? The several experiences and examples that follow might provide some of the possible answers to these questions.
Examples of Improved Performance
The fall season had begun here in the northern hemisphere. It was the time for the annual renovation of some of the shady areas in my lawn with planting of a suitable blend of cool season lawn species to produce a nice green winter lawn. I purchased the seeds needed, emptied them into a large plastic bucket, sprinkled them with water while vigorously stirring to ensure even distribution of the water, and placed a plastic bag over the bucket. Every day through the 7th day I removed the plastic bag applied more moisture as needed and aerated the seeds by stirring them. On the 8th day I spread the seeds on a plastic sheet to allow any surface moisture to evaporate and then planted them on the renovated areas watering them well after planting and again on the 9th day. On the 10th day the renovated areas were covered with emerged green seedlings. As happens every year, some folk in our neighborhood who had observed me planting the seeds came over to ask what kinds of seeds I used to produce a green lawn in 2 days and where could they get some. They were not, of course, aware of the things I had done during the 7 days preceding the planting! One of the neighbors had also planted seeds of the same brand and blend from the same store and had watered them periodically but there was very little emergence even after nearly 3 weeks. The performance of the seeds I planted, therefore, was dramatically improved without any change in their quality status. Performance of the seeds I planted was, of course, improved by a primitive form of "priming" or "osmoconditioning" I learned as a teenager from a great old gardener on a nearby farm. He always mixed seeds of the many vegetable crops he planted with moist sand about a week or so before planting to accelerate emergence.
Seedling emergence and establishment for many of the semi-dwarf rice varieties are improved by treatment of the seeds with gibberellin to increase elongation of the mesocotyl an organ important for emergence. Thus, rice crop production is or can be significantly improved by improving seed performance without any change in seed quality status. Based on some work I did in the early 1960s a few years after gibberellin was discovered the rate of germination and emergence of centipede grass (Eremochloa ophiuroides), a lawn species, is greatly accelerated by treatment with gibberellin. In this case, however, I consider that the improvement in performance is achieved by a change or improvement in seed quality. Centipede grass seeds retain dormancy for a long time which prevents or delays germination and emergence. Dormancy is certainly an attribute of physiological seed quality. Since performance is improved through the release of dormancy with gibberellin, physiological seed quality is changed from dormant to non-dormant. Many other examples of confounding seed performance and quality improvements could be mentioned but we would only get much deeper into semantics and definitions.
I must state here that this final installment of the essay on seed performance is turning out much differently than originally planned as a result of a very interesting and, maybe, prescient editorial note I read just a few days ago in a leading seed trade magazine with the provocative title, The End of Seed Quality
The End of Seed Quality
My immediate impression on "glancing" over the editorial note was that it was a minor appendix to the "end of this or that" literary genre that surfaces from time to time: e.g., Francis Fukuyama's, The End of History (1992); John Horgan's, The End of Science (1996). But, it was narrowly focused on specific components of a subject of long and deep professional interest and thus certainly not minor to me. So, I read it again and much more slowly, carefully and critically. The author's main thesis is that since the major suppliers of maize and soybean seeds have already pushed or are pushing physical seed quality to the maximum limits, it is rapidly losing its position as a marketing feature and becoming just a rather ordinary marketable "commodity." Thus, The End of Seed Quality will soon come when all significant seed suppliers have accessed and claim the seed quality commodity, thus, eliminating it as an important basis for consumer differentiation among suppliers. After advancing the question of "What is the Next Step," the author poses some very intriguing additional rhetorical questions: "What is the next step - scanning seed twice with a color sorter? How much more refinement in seed quality is possible? How much more added value can future quality enhancements deliver to the customer?"
In considering the next step the author more-or-less dismisses a focus on novel genetic traits because current practices of product and trait licensing lead to rapid acquisition and spread of traits among suppliers. Similarly, agronomic performance, e.g., yield, is not give much weight as a competitive edge for seed suppliers as yields are becoming a commodity much like quality. Since seed suppliers all tend to claim yield or performance advantages with some level of supporting data the consumer is again left without means to differentiate among seed suppliers, except maybe price, which quickly disappears under vigorous competition. Interestingly, the author in conclusion suggests that one good opportunity for a supplier to gain a competitive advantage is in the arena of information, i.e., providing quality and value-added information on seed products in ways consumers can understand and use. But, I not as optimistic as the author about the marketability of information in these times of an information overload in many areas and on many subjects including crop varieties and their seeds.
I have no real argument with the author's thesis that for maize and soybean seeds in the U.S. the end of physical seed quality may almost be on hand. I'm mindful that a colleague and highly respected seed researcher informed me about 6 - 7 years ago that he was quitting work on maize and soybean seeds to focus on some lesser researched kinds of seeds because there was not much left to do on maize and soybeans. I had begun to feel the same way about the time I retired in 1995. I do not, however, accept extension of the thesis to the seeds of other important crops in most production areas in the U.S. and other countries. Many seed quality problems still need to be resolved to lessen the limitation of poor seed performance on crop production. And, I continue to believe that the proper development and marketing of performance enhancing treatments such as osmoconditioning, applied gibberellin and other phytoactive chemicals, acid and mechanical hulling and scarification, coatings to avoid imbibitional injury or "schedule" emergence at more favorable times under more favorable conditions, and so on, can provide innovative suppliers with significant competitive advantages and consumers with viable choices among suppliers.
I agree with the author of "the end of seed quality" that for the foreseeable future the use of more and more high-tech conditioning equipment on the seeds of most major crops will result mostly in more attractive seeds with little or no improvement in performance. Eventually and hopefully, however, a device or devices might be developed that can sort seeds on the basis of intrinsic physiological traits, specific performance capabilities, and or infestation/infection with undesirable micro-organisms.
Finally, I have long believed that dramatic improvements in seed quality and performance could be achieved through the inheritance avenue. It is surely feasible in the present era of "trait" crops and "trait" agriculture that traits can be identified and developed that dramatically improve the performance of seeds in places, at times and under conditions where performance is usually severely impaired. And, it can be hoped that some major identifiers and developers of crop traits will recognize opportunity and allocate adequate attention and resources to improving the inherent potential of seed performance.
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