The development of homozygous maize inbreds over two generations

Abstract

A new method of deriving maize inbreds lines over two generations by the development of dihaploids was presented in this paper. A German inbred line RWS was used as a haploid inductor. This inbred encompasses two marker genes: R1-nj, which colors the endosperm and the germ blue, and pl-1, which colors stalk purple. The RWS inbreds was used as a male component in the first generation for crosses to five genotypes developed from crosses of elite maize inbred lines (F1 generation). Gametes of these genotypes crossed to the inbred RWS resulted in a certain number of kernels with the white germ and blue stains on the endosperm, pointing out that the endosperm was fertilized, but the ovum was not. It remained haploid, and it was only stimulated to a further division and a formation of a haploid germ. Such developed kernels were germinated, then treated with colchicine and derived plants were planted in the field. This paper presents the percentage of both, haploid induction for each of five progenies and derived F1 plants. The percentage of the haploid production efficiency was estimated for each of five genotypes. The potential importance of this model in maize breeding and selection was discussed.

U radu je prikazana nova metoda dobijanja inbred linija kukuruza u roku od dve generacije putem stvaranja dihaploida. U ovu svrhu korišćen je induktor haploida, nemačka inbred linija RWS. Ova linija sadrži dva marker gena: R1-nj, koji ostavlja plavu boju na endospermu i klici, i pl-1, koji boji stablo u ljubičasto. RWS linija je u prvoj generaciji korišćena kao otac za ukrštanje sa pet genotipova dobijenih ukrštanjem elitnih inbred linija kukuruza (F1 generacija). Gamete tih genotipova ukrštene sa RWS linijom dale su izvestan broj zrna koja imaju plavo obojenje na endospermu, ali belu klicu, što je indikacija da je došlo do oplodnje endosperma ali ne i jajne ćelije. Ona je ostala haploidna, a samo je stimulisana na dalju deobu i formiranje haploidne klice. Ovako dobijena zrna su naklijana, a zatim tretirana kolhicinom i dobijene su dihaploidne biljke koje su posađene u polju. U radu je dat je procenat indukcije haploida za svako od pet potomstava i procenat dobijenih F1 biljaka. Za svaki od pet genotipova izračunat je procenat uspešnosti dobijanja dihaploida. Diskutovan je potencijalni značaj ove metode u selekciji kukuruza.