ارزﯾﺎﺑﯽ ﻣﺰرﻋﻪ اي ﺗﻨﺶ ﮐﻮﺗﺎه ﻣﺪت ﮔﺮﻣﺎ ﻗﺒﻞ و ﺑﻌﺪ از ﮔﻠﺪﻫﯽ ﺑﺮ ﻋﻤﻠﮑﺮد و اﺟﺰاي ﻋﻤﻠﮑﺮد داﻧﻪ ﮔﻨﺪم ﻧﺎن ﺑﻬﺎره در ﺷﺮاﯾﻂ آب و ﻫﻮاﯾﯽ اﻫﻮاز

Field evaluation of short-term heat stress prior and after flowering on the grain yield and its components in spring bread wheat under warm climate of Ahvaz

ﺑﻪﻣﻨﻈﻮر ﺑﺮرﺳﯽ دورهﻫﺎي ﮐﻮﺗﺎهﻣﺪت ﺗﻨﺶ ﮔﺮﻣﺎ ﺑﺮ ﻋﻤﻠﮑﺮد و اﺟﺰاي ﻋﻤﻠﮑﺮد داﻧﻪ ﮔﯿﺎه ﮔﻨﺪم ﻣﺰرﻋﻪ آزﻣﺎﯾﺶ ﺣﺎﺿﺮ در دو ﺳﺎل زراﻋﯽ 1392-93 و 1393-94 در ﻣﺰرﻋﻪ ﺗﺤﻘﯿﻘﺎﺗﯽ داﻧﺸﮕﺎه ﻋﻠﻮم ﮐﺸﺎورزي و ﻣﻨﺎﺑﻊ ﻃﺒﯿﻌﯽ ﺧﻮزﺳﺘﺎن ﺑﻪ ﺻﻮرت ﺑﻠﻮكﻫﺎي ﻧﻮاري در ﺳﻪ ﺗﮑﺮار اﺟﺮا ﮔﺮدﯾﺪ. ﺗﯿﻤﺎرﻫﺎي آزﻣﺎﯾﺸﯽ ﺷﺎﻣﻞ ﭼﻬﺎر ژﻧﻮﺗﯿﭗ ﮔﻨﺪم ﺑﻬﺎره ﺑﻮد. ﺗﻨﺶ ﮔﺮﻣﺎ )ﺣﺪاﮐﺜﺮ 35 درﺟﻪ ﺳﺎﻧﺘﯽ-ﮔﺮاد( ﺑﺎ ﻧﺼﺐ اﺗﺎﻗﮏﻫﺎي ﺗﻮﻟﯿﺪ ﺗﻨﺶ ﺣﺮارﺗﯽ ﺑﺮ روي ﮐﺮتﻫﺎ اﻋﻤﺎل ﮔﺮدﯾﺪ. ﺑﻮﺗﻪﻫﺎي ﮔﻨﺪم ﺑﻪ ﻣﺪت ﺳﻪ روز ﻣﺘﻮاﻟﯽ در ﻣﺮﺣﻠﻪ ﻇﻬﻮر ﺳﻨﺒﻠﻪ و ﯾﺎ در اﺑﺘﺪاي ﺗﺸﮑﯿﻞ داﻧﻪ در ﻣﻌﺮض ﺗﻨﺶ ﮔﺮﻣﺎ ﻗﺮار ﮔﺮﻓﺘﻨﺪ. ﻧﺘﺎﯾﺞ ﺗﺠﺰﯾﻪ وارﯾﺎﻧﺲ ﻣﺮﮐﺐ ﻧﺸﺎن داد اﺧﺘﻼﻓﺎت ﻣﻌﻨﯽداري در ﺳﻄﻮح ﺗﻨﺶ ﮔﺮﻣﺎ و ﺻﻔﺎت رﻗﻢﻫﺎ وﺟﻮد دارد. ﮐﺎﻫﺶ ﻋﻤﻠﮑﺮد داﻧﻪ ﻧﺎﺷﯽ از ﺗﻨﺶ ﮔﺮﻣﺎي ﮐﻮﺗﺎه ﻣﺪت در رﻗﻢ ﻣﺎرون ﺑﯿﺸﺘﺮﯾﻦ )26 درﺻ(ﺪ و در رﻗﻢ اﺗﺮك ﮐﻤﺘﺮﯾﻦ )14/8 درﺻ(ﺪ ﺑﻮد. ﻫﻤﺒﺴﺘﮕﯽ ﻣﺜﺒﺖ و ﻣﻌﻨﯽداري ﺑﯿﻦ ﻋﻤﻠﮑﺮد داﻧﻪ ﺑﺎ ﺗﻌﺪاد داﻧﻪ در ﺳﻨﺒﻠﻪ در ﻫﺮ دو ﺳﺎل وﺟﻮد داﺷﺖ. ﺗﻨﺶ ﮔﺮﻣﺎي ﮐﻮﺗﺎه ﻣﺪت ﺳﺮﻋﺖ ﭘﺮ ﺷﺪن داﻧﻪ رﻗﻢﻫﺎ را 16/4 درﺻﺪ اﻓﺰاﯾﺶ وﻟﯽ ﻃﻮل دوره ﭘﺮ ﺷﺪن داﻧﻪ را 23/8 درﺻﺪ ﮐﺎﻫﺶ داد. ﺑﺮ اﺳﺎس ﻧﺘﺎﯾﺞ اﯾﻦ آزﻣﺎﯾﺶ رﻗﻢﻫﺎي اﺗﺮك، ﭼﻤﺮان و اروﻧﺪ از ﻃﺮﯾﻖ ﺗﻌﺪاد داﻧﻪ در ﺳﻨﺒﻠﻪ و وزن ﻫﺰار داﻧﻪ ﻣﺘﺤﻤﻞ ﺑﻪ ﮔﺮﻣﺎ ﺷﻨﺎﺧﺘﻪ ﺷﺪﻧﺪ.

To study the effects of short terms of heat stress on grain yield and its components of wheat field studies were laid out in a strip block design with four replicates at Khuzestan Agricultural Sciences and Natural Resources University in 2013 and 2014. Four wheat varieties were exposed to heat stress (maximum 35 °C) during three days in the field with a portable purpose-built heat chamber in two different stages, near heading (H1) and early grain set (H2). The results of combined analysis of variance showed that there were significant differences between heat stress levels and the traits of varieties. The decrease in grain yield due to short-term heat stress was highest (26%) in Maroon and lowest in Atrak (14.8%). There was a significant positive correlation between grain yield and number of grains per spike in both years. Short-term heat stress increased grain filling rate by 16.4% but decreased grain filling duration by 23.8%. Based on the results of this experiment, Atrak, Chamran and Arvand cultivars were identified as heat tolerant by number of grains per spike and 1000-kernel weight.