scholarly journals A Thermotolerant Variant of Rubisco Activase From a Wild Relative Improves Growth and Seed Yield in Rice Under Heat Stress

2018 ◽  
Vol 9 ◽  
Author(s):  
Andrew P. Scafaro ◽  
Brian J. Atwell ◽  
Steven Muylaert ◽  
Brecht Van Reusel ◽  
Guillermo Alguacil Ruiz ◽  
...  
1997 ◽  
Vol 77 (1) ◽  
pp. 97-99 ◽  
Author(s):  
L. V. Gusta ◽  
B. J. O'Connor ◽  
R. S. Bhatty

The effect of a 5 °C chilling treatment at the seedling stage on days to flower, yield and oil quality and quantity was determined for seven cultivars of flax (Linum usitatissimum L.). Three days of chilling delayed flowering in Dufferin, McGregor and NorLin, whereas 5 d of chilling delayed flowering in all cultivars except Andro and Noralta. Seven days of chilling reduced the seed yield of only McGregor, Norlin, NorMan and Vimy. The effect of a 40 °C heat stress at the flowering stage on yield and oil composition was determined for the same seven cultivars. A heat stress of 40 °C for 3 d reduced the seed yield of NorMan, whereas, a 5 d stress reduced the seed yield of all cultivars except McGregor and Noralta. The composition of the oil was not affected by the heat stress. These results suggest genetic variability exists among flax cultivars for tolerance to chilling and heat stresses. Controlled tests can be used to select superior stress tolerant genotypes. Key words: Flax, chilling, heat, flowering, yield


2020 ◽  
Vol 158 (4) ◽  
pp. 255-261
Author(s):  
Jorge Alvar-Beltrán ◽  
Leonardo Verdi ◽  
Anna Dalla Marta ◽  
Abdalla Dao ◽  
Roberto Vivoli ◽  
...  

AbstractQuinoa (Chenopodium quinoa Willd.) is capable of adapting to multiple environments and tolerating abiotic stresses including saline, drought and frost stress conditions. However, the introduction of quinoa into new environments has disclosed adaptation challenges. The principle factor affecting crop pollination is heat stress at flowering, which leads to sterile plants. To investigate the effect of high temperatures during the sensitive phenological phases, flowering and seed germination, a Danish-bred cultivar (cv. Titicaca) was grown in climatic chambers. Selection of the cv. Titicaca was based on the fact that it is the most extensively used cultivar in the Sahel and Middle East and North African region. The results of this research demonstrated that temperatures exceeding 38 °C hindered seed germination and pollination, and therefore, seed yield at harvest. At 38 °C, seed yield losses were 30%, whilst seed germination percentage declined below 50%. In addition, the results of the present research were compared with field observations from Burkina Faso in order to determine the spatiotemporal suitability of this crop with respect to temperature stress. Although many other abiotic stresses need to be considered when defining crop calendars (e.g. heavy precipitation in July and August), this research proposes the following growing periods to avoid heat-stress conditions at flowering: Sahel (July–September and November–February), Soudano–Sahel (June–February) and Soudanian zone (all year round).


2017 ◽  
Vol 68 (9) ◽  
pp. 823 ◽  
Author(s):  
Rashmi Awasthi ◽  
Pooran Gaur ◽  
Neil C. Turner ◽  
Vincent Vadez ◽  
Kadambot H. M. Siddique ◽  
...  

Drought and heat stress are two major constraints that limit chickpea (Cicer arietinum L.) yield, particularly during seed filling. The present study aimed (i) to assess the individual and combined effects of drought and heat stress on oxidative metabolism during seed filling, and (ii) to determine any genetic variation in oxidative metabolism among genotypes differing in drought and heat tolerance and sensitivity. The plants were raised in outdoor conditions with two different times of sowing, one in November (normal-sown, temperatures <32°C−20°C (day–night) during seed filling), and the other in February (late-sown, temperatures >32°C−20°C (day–night) during seed filling). Plants were regularly irrigated to prevent any water shortage until the water treatments were applied. At both sowing times, the drought treatment was applied during seed filling (at ~75% podding) by withholding water from half of the pots until the relative leaf water content (RLWC) of leaves on the top three branches reached 42–45%, whereas leaves in the fully irrigated control plants were maintained at RLWC 85–90%. Drought-stressed plants were then rewatered and maintained under fully irrigated conditions until maturity. Several biochemical parameters were measured on the leaves and seeds at the end of the stress treatments, and seed yield and aboveground biomass were measured at maturity. Individual and combined stresses damaged membranes, and decreased PSII function and leaf chlorophyll content, more so under the combined stress treatment. The levels of oxidative molecules (malondialdehyde (MDA) and H2O2) markedly increased compared with the control plants in all stress treatments, especially across genotypes in the combined heat + drought stress treatment (increases in leaves: MDA 5.4–8.4-fold and H2O2 5.1–7.1-fold; in seeds: MDA 1.9–3.3-fold and H2O2 3.8–7.9-fold). The enzymatic and non-enzymatic antioxidants related to oxidative metabolism increased under individual stress treatments but decreased in the combined heat + drought stress treatment. Leaves had higher oxidative damage than seeds, and this likely inhibited their photosynthetic efficiency. Yields were reduced more by drought stress than by heat stress, with the lowest yields in the combined heat + drought stress treatment. Heat- and drought-tolerant genotypes suffered less damage and had higher yields than the heat- and drought-sensitive genotypes under the individual and combined stress treatments, suggesting partial cross-tolerance in these genotypes. A drought-tolerant genotype ICC8950 produced more seed yield under the combined heat + drought stress than other genotypes, and this was associated with low oxidative damage in leaves and seeds.


2016 ◽  
Vol 30 (2) ◽  
pp. 118-151 ◽  
Author(s):  
Kalpna Bhandari ◽  
Kadambot H. M. Siddique ◽  
Neil C. Turner ◽  
Jagmeet Kaur ◽  
Sarvjeet Singh ◽  
...  

Author(s):  
Chandan Kumar ◽  
S. B. Mishra ◽  
Nilanjaya . ◽  
Chandra Mohan Singh

Forty genotypes of greengram were studied to ascertain the genetic variability and trait association among some important morpho-physiological traits and agro-meterological indices under heat stress condition. The results indicated that both GCV and PCV estimates were high for photo thermal index, heat use efficiency and seed yield. High heritability coupled with moderate genetic advance as per cent of mean was recorded for photo-thermal unit and relative temperature depression indicated that involvement of both additive and non-additive type of gene action and possibilities of effective selection for improvement of these traits. Seed yield showed significant and positive association with days to maturity, growing degree days, relative temperature depression and heat use efficiency. Based on variability, association and path analysis; heat use efficiency, maturity, photo thermal index and growing degree days were found most contributing indices/ traits should be considered as selection criteria for discrimination of outstanding greengram genotypes under heat stress condition.


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