Combined S1-TC-RRS with consideration of CMS and dihaploids in maize

Abstract

Herein, we present the combined S1-HS-RRS method using inbred testers (S1-TC-RRS) as a long-term maize breeding program, which increases the frequency of favorable alleles and maintains genetic variability in two genetically opposite populations. The method improves two different genetic sources simultaneously, where S1 families, developed by selfing phenotypically superior plants from both breeding populations are crossed with opposite inbred testers for specific combining ability selection, accompanied by selection of S1 families per se. A certain percentage of the evaluated S1 families is used for the next TC-RRS selection cycle. Maternal haploids from the selected S1 lines of each cycle of S1-TC-RRS can serve to produce elite 100% homozygous inbred lines (dihaploids) in a short time, which decreases the time and expenses of the selection cycle and influence the efficiency of seed production, as well as, variety protection rights. This elite lines than can be converted to CMS versions (paternal haploids), for the seed production, which lowers the costs of it.

Prestavlja se kombinovani S1-HS-RRS metod uz korišćenje inbred testera (S1-TCRRS), kao dugoročni program u oplemenjivanju kukuruza, koji povećava frekvenciju poželjnih alela i održava genetičku varijabilnost dve genetički opozitne populacije. Metodom se u isto vreme popravljaju dva genetički opozitna izvora, gde se S1 familije, dobijene samooplodnjom fenotipski superiornih biljaka iz obe populacije, ukrštaju sa opozitnim inbred testerom radi selekcije na posebne kombinacione sposobnosti, uz istovremenu selekciju S1 familija per se. Određen procenat ispitivanih S1 familja se koristi za sledeći TC-RRS ciklus selekcije. Uz pomoć metode majčinskih haploida, iz odabranih S1 linija svakog S1-TC-RRS ciklusa mogu se dobiti 100% homozigotne elitne inbred linije (dihaploidi) za kratko vreme, što smanjuje vreme i troškove selekcionog ciklusa, a utiče na efikasnost semenske proizvodnje i zaštitu oplemenjivačkih prava. Ove elitne inbred linije mogu se prevesti na cms verziju (ocinski haploidi), što smanjuje troškove u semenskoj proizvodnji.