Utility of basic research in plant/crop physiology in relation to crop improvement: a review and a personal account

Abstract

Utilidade da pesquisa básica em fisiologia vegetal e em fisiologia da produção em relação ao melhoramento das culturas: uma revisão e uma análise pessoal: A pesquisa e o desenvolvimento agrícola têm função essencial no desenvolvimento econômico das nações, provendo segurança alimentar para uma população em constante crescimento demográfico. Em países desenvolvidos, as lacunas entre a produção potencial e a produção real são sobremodo estreitas, devido a uma combinação de tecnologias avançadas, novas variedades altamente produtivas e aplicação de agroquímicos em sistemas de produção altamente mecanizados. Na maioria daqueles países, a produção agrícola supera a demanda nacional, resultando em excedentes para a exportação. Em muitos países em desenvolvimento, entretanto, a produtividade agrícola está ainda muito abaixo de seu potencial devido a limitações técnicas e sócio-econômicas. Déficit alimentar é a norma em países pobres e subdesenvolvidos, os quais requerem vultosas importações de alimentos. Para aliviar parcialmente essa situação, pesquisas de cunho agrícola devem ser reforçadas. Como ramos das ciências básicas, a fisiologia vegetal e a fisiologia da produção têm sido freqüentemente criticadas por não traduzirem seus resultados de pesquisa em melhoria da produtividade. Este artigo é focado nesse tema, apresentando uma avaliação das realizações pretéritas da pesquisa fisiológica e de seus impactos sobre o melhoramento das culturas e sobre a produção de alimentos. Discutem-se deficiências e limitações de pesquisas isoladas e de pouca relevância, juntamente com opiniões do cientista sobre como pesquisas efetivas na área da fisiologia devem ser conduzidas e integradas dentro de equipes de pesquisa multidisciplinares associadas ao melhoramento vegetal. Exemplos de pesquisas de sucesso na fisiologia da produção e suas contribuições para aumentar a produtividade agrícola são apresentados. Todos esses aspectos apontam para a necessidade de pronto financiamento da pesquisa básica por setores públicos e privados de países desenvolvidos. Palavras-chave: agricultura, ecofisiologia, ecossistemas, estresse hídrico, fotoperíodo, fotossíntese C 4 , hormônios, melhoramento, produtividade, solo, tolerância à seca Agricultural research and development plays an essential role in a nation s economic development, providing for food security for an ever-increasing population. In developed countries, the gap between potential and actual yield is largely closed because of a combination of advanced technologies, high-yielding new varieties and the application of agrochemicals in highly mechanized production systems. In most of these countries, agricultural production exceeds national demand, resulting in excess products for export. In many of the developing countries, however, agricultural productivity is still far below what it should be because of multiple technical and socio-economic constraints. Food deficits are the norm in poor and middle-income countries, requiring expensive food imports. To partially alleviate this situati...

Physiological characteristics of cassava tolerance to prolonged drought in the tropics: implications for breeding cultivars adapted to seasonally dry and semiarid environments

“…The role of physiological research in crop improvement and cropping systems management has recently been reviewed (El-Sharkawy, 2006b). As a branch of basic science, plant physiological research has a fundamental role in advancing the frontier of knowledge that is essential for the better understanding of plants and their interactions with surrounding biophysical environments.…”

“…Those authors concluded that field research is the only valid ecosystem research in studying plant water relations and crop photosynthesis in relation to productivity. Until recently, the controlled-environment and greenhouse potted-plant scientists (many of whom were members of national science academies) controlled the plant photosynthesis and water relations research and often invoked the misuse of the terminology "adaptation to stress" for "acclimation to stress" to protect their domination over the public-funded scientific establishment and to cover up their failure in contributing to the early discoveries of the C 4 photosynthesis and its implications for plant water use efficiency (El-Sharkawy, 2005, 2006bHesketh, 1965, 1986;Begonia and Begonia, 2007). This is not a very good example to teach young people about how science is done nor an efficient way to manage public-funded research.…”

Seasonal Variation of Some Bioactive Compounds and Physiological Characteristics in Peony (Paeonia lactifl ora Pall.)

“…Seasonal variation of P. lactifl ora decrease ratio Rfd correlates with the potential CO 2 fi xation rate of leaves. When Rfd ≥ 2.5 the normal photosynthetic activity is indicated and on the other hand, at Rfd < 1 the low photosynthetic activity was confi rmed (El-Sharkawy, 2006). The chlorophyll fl uorescence indices were measured during the vegetation period of P. lactifl ora.…”

Pioneering research on C₄ leaf anatomical, physiological, and agronomic characteristics of tropical monocot and dicot plant species: Implications for crop water relations and productivity in comparison to C₃ cropping systems

“…Zelitch 1971Zelitch , 1982 on what the agronomists did some being done at his location at Connecticut Agricultural Experiment Station, carefully citing most of the proper sources; the early agronomic work was also cited enough to win two citation classics. The American mainstream plant physiological-biochemical photosynthetic scientists also missed the Berkeley, CA, ground-breaking work on photosynthetic C 3 biochemistry (for the history of the elucidation of the C 3 cycle see Calvin 1989), as well as work on internode-dwarfing and flowering genes and their role in the photosynthesis of crop canopies and subsequent yield that impacted positively agricultural productivity and food security worldwide in the past five decades (the so-called "Green Revolution", mainly funded by non-profit private agencies) (Borlaug 1983, El-Sharkawy 2005, 2006a, Begonia and Begonia 2007, Andre 2006. American mainstream plant physiologicalbiochemical photosynthetic scientists seem to have drifted somewhat during all this.…”

“…Thus, in these complex and expensive FACE trials that require large interdisciplinary/interinstitution team of researchers, it would be of importance to extensilvely study effects of edapho-climatic conditions, particularly soil-waternutrient factors and air humidity within crop canopy, and to construct complementary crop-soil-atmosphere submodels. Such information is essential in order to elucidate mechanisms underlying responses to elevated CO 2 in the field, to maximise benefit/cost ratio of doing research as well as to reasonably predict the effect of global climate change on agricultural productivity (Rosenzweig and Parry 1994, El-Sharkawy 2005, 2006a, IPCC 2006. In any case, however, these data indirectly illustrate the invalidity of the high estimates of CO 2 around Rubisco in bundle sheath cells of C 4 plants via the so-called 'CO 2 -concentrating mechanism' that were based on unrealistic theoretical models.…”