Sorghum , in the semi-arid environment of the South Italy is cultivated in the summer season, with the use of water for irrigation. The early sowings could allow the crop to escape part of the dry season. However the thermal requirements of sorghum for seed germination (>10°C) limit the use of early sowings. The seed treatment which revealed to be useful to improve the seeds germination performance is osmopriming which is a controlled hydration of the seed a solution at low water potential, where pre-germination metabolic process are activated. Moreover the management of irrigation play a primary role in the agriculture actives in Mediterranean environment. One of the more innovative techniques of water saving is the Partial Rootzone Driyng (PRD) a modified form of Deficit Irrigation which involves the irrigation of only a half at the rootzone at each watering. The aim of this research was to individuate out of different fiber and sweet sorghum varieties those better responding to role water deficit without diminishing yield and those better germinating at sub-optimal temperatures. Further objective was to verify the effect of osmopriming to improve the seed germination in sub-optimal temperature condition. In order to achieve the objectives the following lines of research were carried out. The line 1 and 3 have studied the response to the water stress of different genotypes of fiber and sweet sorghum, evaluating the yield and ecophysiology of the crop grown in early and late sowing; the line 2 have to face the screening of the genotypes to resistance to low temperatures during germination phase in sorghum cultivar; the line 4 has the objective to evaluate the effect of osmpriming on the seed germination at different temperatures in controlled conditions and in open air in early sowing dates; finally the line 5, carried out in Kemptville Canada, has studied the effects of plant density on the growth and yield of total sugar in sweet sorghum varieties. The results of the line 1 has highlight a good productive capacity of fiber and sweet sorghum , as biomass crop in Mediterranean environment. The water required have affected significantly the yield of dry biomass. The late sowing (July) and the abrupt decreasing of the temperature in the autumn season, before the harvest did not allow to reach the complete ripening of seeds. Yield ranged in, the average of genotypes, between 13.7 t ha-1 in I100 and 8.6 in I0. Besides the I50 PRD treatment produced 12.0 t ha-1 confirm the validity of the techniques. The irrigation water use efficiency was improved by the PRD treatment. The results of line 2 pointed one significantly difference for the low temperature resistance in fiber and sweet sorghum variety in controlled temperatures. In particular selection criteria are a low base temperature and reduced thermal time. The results of line 3 confirmed an influence of water regime to all varieties the dry biomass yield in the average of treatments and genotypes types varied significantly among the studied factors. In the best irrigation condition (I100) the yield was equal to 20.8, whereas in 50% and 0% treatment have obtained values of 16.2 and 6.2 t ha-1 respectively. The most productive variety was Sugargraze with a dry yield of 44.9 t ha-1 in I100 treatment. The PRD allowed to obtain water sowing of 35% of water compared to I100 treatment and better volume of water use efficiency. The results obtained by the line 4 confirm that the minimum thermal temperature for seed germination of these four varieties under study in laboratory was 8-10°C. However in open air the germination was lower demonstrating that non controlled thermal conditions higher temperatures are needed. The results received a beneficial effect from osmopriming more in laboratory than in open air. Finally the results of line 5 confirmed the low yield performance of sweet sorghum when cultivated in low temperature environmental.
Il sorgo, negli ambienti semi-aridi del Sud Italia viene coltivato nella stagione estiva, richiedendo pertanto l uso dell acqua di irrigazione. Le esigenze termiche del sorgo per la germinazione del seme (>10°C) limitano l adozione di semine precoci. Un trattamento al seme rivelato utile nel migliorare le perfomance germinative del seme in condizioni subottimali è l osmopriming, che consiste in una idratazione controllata del seme. La gestione della irrigazione gioca un ruolo di primaria importanza. Una delle tecniche innovative di risparmio idrico è la Partial Rootzone Drying (PRD), che coinvolge l'irrigazione solo di una parte della zona radicale ad ogni turno di irrigazione. Lo scopo di questa ricerca è stato di individuare tra diversi genotipi di sorgo zuccherino e da fibra quelli che meglio rispondevano alle restrizioni idriche non penalizzando le produzioni e quelli che germinavano a temperature subottimali. Ulteriore obiettivo è stato quello di verificare gli effetti dell osmopriming al fine di migliorare le perfomance germinative del seme in condizioni subottimali. Lo studio durante il corso di dottorato, è stato articolato in 5 linee; le linee 1 e 3, hanno preso in esame lo studio della risposta allo stress idrico di differenti genotipi di sorgo, valutando le caratteristiche produttive, ed agronomiche della coltura seminata in epoca ritardata e anticipata; la linea 2, ha affrontato gli aspetti relativi allo screening genotipico per la resistenza alle basse temperature in fase di germinazione in cultivar di sorgo; la linea 4, ha avuto lo scopo di valutare l effetto dell osmopriming sulle caratteristiche germinative del seme a differenti temperature in condizioni controllate e in pieno campo in epoche di semina anticipate; infine la linea 5, svolta in Canada, ha studiato gli effetti dell investimento unitario sulla crescita e sulla produzione di zuccheri in genotipi di sorgo zuccherino. I risultati della linea 1 hanno evidenziato una discreta capacità produttiva del sorgo, come coltura da biomassa per energia seminata in epoca ritardata nell ambiente mediterraneo. I regimi irrigui allo studio hanno influenzato in maniera significativa la produzione di biomassa. La semina ritardata (Luglio), non ha consentito alla coltura il raggiungimento della maturazione fisiologica. Le rese in biomassa secca oscillavano nella media dei genotipi, tra 13,7 t ha-1 della tesi I100 e 8,6 t ha-1 nella tesi I0. Per contro la tesi I50 PRD, ha fatto registrare una resa di 12,0 t ha-1, confermando la validità di questa tecnica nel risparmiare risorsa idrica. La WUE, è migliorata con la tecnica irrigua PRD rispetto alla tesi I100 mostrando un certo grado di validità di questa tecnica. I risultati della linea 2, hanno evidenziato differenze significative per la resistenza al freddo riscontrate in tipi di sorgo da biomassa in laboratorio a temperatura controllata. Criteri per la selezione sono una bassa soglia termica e somme termiche ridotte. I risultati della linea 3, hanno confermato una buona capacità produttiva del sorgo da biomassa in epoca anticipata in ambiente mediterraneo. Il ciclo colturale è stato influenzato dalle tesi irrigue. I valori di biomassa secca sono stati pari a 20,8, 16,2 e 6,2 t ha-1 rispettivamente per le tesi 100%, 50% e 0%. La cultivar più produttiva si è dimostrata essere Sugargraze in tesi I100 con una produzione di biomassa secca di 44,9 t ha-1 . La tecnica PRD ha permesso di risparmiare il 35% di acqua rispetto alla tesi I100. I risultati ottenuti dalla linea 4, confermano come il minimo termico per la germinazione dei semi delle quattro cultivar allo studio rilevato in laboratorio sia intorno a 8-10°C. I semi hanno beneficiato dell osmopriming, più in laboratorio che in campo. Infine i risultati della linea 5, hanno confermato le scarsa potenzialità produttiva del sorgo da biomassa allorchè coltivato in ambiente a clima rigido quale quello canadese
Caratterizzazione agronomica e fisiologica di genotipi di sorgo zuccherino per la produzione di bioetanolo / Saita, Alessandro. - (2011 Dec 09).
Caratterizzazione agronomica e fisiologica di genotipi di sorgo zuccherino per la produzione di bioetanolo
SAITA, ALESSANDRO
2011-12-09
Abstract
Sorghum , in the semi-arid environment of the South Italy is cultivated in the summer season, with the use of water for irrigation. The early sowings could allow the crop to escape part of the dry season. However the thermal requirements of sorghum for seed germination (>10°C) limit the use of early sowings. The seed treatment which revealed to be useful to improve the seeds germination performance is osmopriming which is a controlled hydration of the seed a solution at low water potential, where pre-germination metabolic process are activated. Moreover the management of irrigation play a primary role in the agriculture actives in Mediterranean environment. One of the more innovative techniques of water saving is the Partial Rootzone Driyng (PRD) a modified form of Deficit Irrigation which involves the irrigation of only a half at the rootzone at each watering. The aim of this research was to individuate out of different fiber and sweet sorghum varieties those better responding to role water deficit without diminishing yield and those better germinating at sub-optimal temperatures. Further objective was to verify the effect of osmopriming to improve the seed germination in sub-optimal temperature condition. In order to achieve the objectives the following lines of research were carried out. The line 1 and 3 have studied the response to the water stress of different genotypes of fiber and sweet sorghum, evaluating the yield and ecophysiology of the crop grown in early and late sowing; the line 2 have to face the screening of the genotypes to resistance to low temperatures during germination phase in sorghum cultivar; the line 4 has the objective to evaluate the effect of osmpriming on the seed germination at different temperatures in controlled conditions and in open air in early sowing dates; finally the line 5, carried out in Kemptville Canada, has studied the effects of plant density on the growth and yield of total sugar in sweet sorghum varieties. The results of the line 1 has highlight a good productive capacity of fiber and sweet sorghum , as biomass crop in Mediterranean environment. The water required have affected significantly the yield of dry biomass. The late sowing (July) and the abrupt decreasing of the temperature in the autumn season, before the harvest did not allow to reach the complete ripening of seeds. Yield ranged in, the average of genotypes, between 13.7 t ha-1 in I100 and 8.6 in I0. Besides the I50 PRD treatment produced 12.0 t ha-1 confirm the validity of the techniques. The irrigation water use efficiency was improved by the PRD treatment. The results of line 2 pointed one significantly difference for the low temperature resistance in fiber and sweet sorghum variety in controlled temperatures. In particular selection criteria are a low base temperature and reduced thermal time. The results of line 3 confirmed an influence of water regime to all varieties the dry biomass yield in the average of treatments and genotypes types varied significantly among the studied factors. In the best irrigation condition (I100) the yield was equal to 20.8, whereas in 50% and 0% treatment have obtained values of 16.2 and 6.2 t ha-1 respectively. The most productive variety was Sugargraze with a dry yield of 44.9 t ha-1 in I100 treatment. The PRD allowed to obtain water sowing of 35% of water compared to I100 treatment and better volume of water use efficiency. The results obtained by the line 4 confirm that the minimum thermal temperature for seed germination of these four varieties under study in laboratory was 8-10°C. However in open air the germination was lower demonstrating that non controlled thermal conditions higher temperatures are needed. The results received a beneficial effect from osmopriming more in laboratory than in open air. Finally the results of line 5 confirmed the low yield performance of sweet sorghum when cultivated in low temperature environmental.File | Dimensione | Formato | |
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