ﺑﻬﺒﻮد ﺗﺤﻤﻞ ﺑﻪ ﺧﺸﮑﯽ ﻋﻠﻒ ﺑﺎغ Dactylis glomerata در ﻧﺴﻞ ﻫﺎي ﭘﻠﯽ ﮐﺮاس ﻣﻨﺘﺨﺐ ﺑﺮ اﺳﺎس ﺳﻄﻮح ﺗﻨﻮع ﻓﻨﻮﺗﯿﭙﯽ و ﻣﻮﻟﮑﻮﻟﯽ

polycross generations based on the levels of phenotypic and molecular diversity

ﭼﮑﯿﺪه ﻫﺪف از اﯾﻦ ﻣﻄﺎﻟﻌﻪ، ﻣﻘﺎﯾﺴﻪ ﺗﺤﻤﻞ ﺑﻪ ﺧﺸﮑﯽ ژﻧﻮﺗﯿﭗ ﻫﺎي ﻋﻠﻒ ﺑﺎغ در دو ﻧﺴﻞ ﭘﻠﯽ ﮐﺮاس و ﻣﺘﻔﺎوت از ﺳﻄﻮح ﺗﻨﻮع ژﻧﺘﯿﮑﯽ واﻟﺪﯾﻦ )ﮔﺮوه ﻫﺎي ﻫﺘﺮوﺗﯿﮏ( ﻣﯽ ﺑﺎﺷﺪ. ﻧﺘﺎج ﻧﺴﻞ اول و دوم ﭼﻬﺎر ﮔﺮوه ﭘﻠﯽ ﮐﺮاس اﯾﺠﺎدﺷﺪه ﺑﺎ واﻟﺪﯾﻦ داراي ﺳﻄﻮح ﻣﺘﻔﺎوت ﺗﻨﻮع ژﻧﺘﯿﮑﯽ )ﮐﻢ و زﯾﺎد( ﺑﺮ اﺳﺎس ﻧﺸﺎﻧﮕﺮﻫﺎي ﻣﻮﻟﮑﻮﻟﯽ و ﺻﻔﺎت ﻣﻮرﻓﻮﻟﻮژﯾﮏ )درﻣﺠﻤﻮع 4 ﮔﺮوه ﻫﺘﺮوﺗﯿﮏ( ﺑﻪ ﺻﻮرت آزﻣﺎﯾﺶ ﻓﺎﮐﺘﻮرﯾﻞ در ﻗﺎﻟﺐ ﻃﺮح ﺑﻠﻮك ﮐﺎﻣﻞ ﺗﺼﺎدﻓﯽ در دو ﺷﺮاﯾﻂ ﻧﺮﻣﺎل و ﺗﻨﺶ رﻃﻮﺑﺘﯽ ﮐﺸﺖ و ازﻧﻈﺮ وﯾﮋﮔﯽﻫﺎي ﺳﯿﺴﺘﻢ رﯾﺸﻪ اي و ﻣﻮرﻓﻮﻟﻮژﯾﮏ ﺑﺮرﺳﯽ ﺷﺪﻧﺪ. ﻧﺘﺎﯾﺞ ﻣﻘﺎﯾﺴﻪ ﻣﯿﺎﻧﮕﯿﻦﻫﺎ ﻧﺸﺎن داد ﮐﻪ ﺗﻨﺶ ﺧﺸﮑﯽ، ﺻﻔﺎت ﻃﻮل رﯾﺸﻪ و درﺻﺪ ﻣﺎده ﺧﺸﮏ ﻋﻠﻮﻓﻪ را ﺑﻪ ﻃﻮر ﻣﻌﻨﯽداري اﻓﺰاﯾﺶ و ﺻﻔﺎت وزن ﺧﺸﮏ ﻋﻠﻮﻓﻪ، وزن ﺧﺸﮏ رﯾﺸﻪ و درﺻﺪ ﻣﺎده ﺧﺸﮏ رﯾﺸﻪ را ﺑﻪ ﻃﻮر ﻣﻌﻨﯽ داري ﮐﺎﻫﺶ داد. ﺗﻔﺎوت ﺑﯿﻦ ﻧﺴﻞ اول و ﻧﺴﻞ دوم ﻓﻘﻂ ﺑﺮاي ﺻﻔﺎت روز ﺗﺎ ﺧﻮﺷﻪدﻫﯽ، درﺻﺪ ﻣﺎده ﺧﺸﮏ ﻋﻠﻮﻓﻪ و ﻃﻮل رﯾﺸﻪ ﻣﻌﻨﯽدار ﺑﻮد. ﻣﻘﺎﯾﺴﻪ ﻣﯿﺎﻧﮕﯿﻦ ﮔﺮوهﻫﺎي ﻫﺘﺮوﺗﯿﮏ ﻧﺸﺎن از ﺗﻔﺎوت ﮔﺮوهﻫﺎ در ﺷﺮاﯾﻂ ﺗﻨﺶ و ﻋﺪم ﺗﻨﺶ رﻃﻮﺑﺘﯽ در دو ﻧﺴﻞ داﺷﺖ. ﺑﺎ اﺳﺘﻔﺎده از ﺗﺠﺰﯾﻪ ﺑﻪ ﻣﺆﻟﻔﻪ ﻫﺎي اﺻﻠﯽ، رواﺑﻂ ﺻﻔﺎت و ارﺗﺒﺎط ﮔﺮوه ﻫﺎي ﻫﺘﺮوﺗﯿﮏ ﺑﺎ ﯾﮑﺪﯾﮕﺮ و ﺑﺎ ﺻﻔﺎت در ﻫﺮ ﻧﺴﻞ و ﺳﻄﺢ رﻃﻮﺑﺘﯽ ﺑﺤﺚ ﻣﯽﺷﻮد.

The purpose of this study was to compare drought tolerance of orchardgenotypes developed from two generations and different levels of genetic diversity of parents (four heterotic groups). Progenies of first and second generation of four groups of polycrosses (each consisted of six parental genotypes) with different levels of genetic diversity (low or high) based on molecular markers and morphological traits (finally four groups) were evaluated as factorial experiment according to a randomized complete block design for root and morphology characteristics. Results of mean comparison showed that drought stress leads to significantly increased in root length and percent of dry matter yield and significantly decreased in dry weight of forage, root dry weight and root dry matter. The difference between first and second generations was significant only for days to ear emergence, forage dry matter percentage and root length. Comparison of the mean between heterotic groups showed differences in stress and non-stress conditions. Using principal components analysis, the relationships of traits and the relationship of heterotic groups to each other and to the traits at each generation and moisture level are discussed.