معادلة للتنبؤ بنسبة التدهور الوراثي في مجتمع F2 للذرة الصفراء

الملخص EN

A field experiment was conducted on the form of the Dept.

of Field Crop Sci.

/ College of Agriculture / University of Baghdad in spring and fall seasons of 2009 and 2010 .

Ten inbreds of maize were planted and crossed to each other to produce single crosses .

In the second season, single crosses were planted along with thin parent to produce three – way and double crosses .

In the third seasons panet and crosses were planted .

Crosses were selfed to produce F2 seeds and increase seeds of inbreds .

In the fourth season, all grin types were planted , and their agronomic traits were evaluated .

Values of P of inbreds , F1 and F2 were calculated for agronomic traits .

The new formula to predict inbreeding depression ( ID ) F2 plant without growing them relied on : relative constant ( χ ) , P and F1 of traits .

It was set up as : ID % = [ ( 1 – χ ) – χP / F1 ] × 100 .

The inbreeding depression obtained was compared to that reported by Ouapadissakoon and Wernswam .

The to values were just fit for all traits tested ; plant grain yield , kernel weight , kernel / ear , rows / ear , leaf area / plant , and plant total dry matter .

However ,the F2 populations used were of three – way and double crosses .

the F2 of single crosses if used ,the formula will stand right .

This formula is very useful to predict inbreeding depression without the need to grow F2 seeds .

whereas , other three formulas were set up to predict means of agronomic traits for inbreds ( parents ) ( P ) , F1 and F2 means P = [ ( 1 – χ ) – ( ID % ) ] × F1 / χ , for predicting : F1 = χP / ( 1 – χ ) – ID% , and for predicting values of F2 = ( 1 – ID % ) F1 .

Results show very high fit for all traits estimated .

Hence, we recommend using these formulas to predict any value mean of any trait of P , F1 , and F2 populations .