etic ▁research ; ▁this ▁P I ▁ 3 1 3 9 7 0 ▁versus ▁race ▁S ▁case ▁involved ▁multi - stage ▁hy brid ization ▁to ▁propag ate ▁a ▁re cess ive ▁gene , ▁pm - S ▁in ▁success ive ▁gener ations , ▁and ▁how ▁this ▁may ▁affect ▁other ▁re cess ive ▁and ▁cod omin ant ▁gen es ▁for ▁resistance ▁to ▁other ▁races ▁of ▁P . ▁x anth ii ▁" rem ains ▁to ▁be ▁determined ". ▁ ▁A ▁ 2 0 0 4 ▁literature ▁review ▁regarding ▁pow der y ▁mil de w ▁races ▁that ▁par as it ize ▁various ▁c uc ur bit ▁plants ▁concluded ▁that ▁" race ▁identification ▁is ▁important ▁for ▁basic ▁research ▁and ▁is ▁especially ▁important ▁for ▁the ▁commercial ▁seed ▁industry , ▁which ▁requires ▁accuracy ▁in ▁declaring ▁the ▁type ▁and ▁level ▁of ▁resistance ▁... ▁in ▁its ▁products ". ▁ ▁However , ▁ident ifying ▁specific ▁races ▁was ▁seen ▁as ▁having ▁little ▁utility ▁in ▁h ort icult ure ▁for ▁choosing ▁specific ▁cultiv ars , ▁because ▁of ▁the ▁rapid ity ▁with ▁which ▁the ▁local ▁path ogen ▁population ▁can ▁change ▁ge ograph ically , ▁season ally , ▁and ▁by ▁host ▁plant . ▁ ▁At ▁least ▁three ▁other ▁E ry si ph aceae ▁fung i ▁can ▁cause ▁pow der y ▁mil de w ▁in ▁c uc urb its : ▁The ▁most ▁frequent , ▁after ▁P . ▁x anth ii , ▁is ▁E rys ip he ▁c ich or ace ar um , ▁the ▁former ▁primary ▁caus al ▁organ ism ▁throughout ▁most ▁of ▁the ▁world . ▁ ▁Pod