Browsing by Author "L. Ram"

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SSR Marker aided introgression for opaque2 allele for development of quality protein maize inbreds
(Cereal Research Non-Profit Company, 2017) R. Singh; L. Ram; R.K.S. Singh; D. Singh Jakhar
Maize protein quality is deficit in essential amino acids, lysine and tryptophan. These constraints of o2 (opaque2) are corrected in genetically improved, hard endosperm QPM (Quality Protein Maize). An integrated strategy of phenotypic selection for endosperm modifiers and molecular marker-assisted foreground and background selection has been used in present study. The QPM donors were, CML 161, DMRQPM 58, CML 176 and CML 141 whereas, normal maize inbreds were CM 212, V338, V361, V336, V341, V351, CM 141 and V335. The inbreds were subjected to parental polymorphism survey between non-QPM and QPM using CIMMYT based three SSR markers, viz. phi057, umc1066 and phi112. Two markers, viz. phi057 and umc1066 exhibited co-dominant reactions, while phi112 was dominant in nature. Finally, two combinations V335 × CML 141 and V351 × CML 141 were considered for conversion program. Foreground selection was exercised using o2 specific marker umc1066 in BC1 and BC2 generations, while background as well as foreground selection was exercised in BC2F3 generation to recover the genome of recurrent parent up to extent of 80 to 100% with the help of SSR markers distributed across the whole maize genome. The tryptophan concentration in endosperm protein was significantly enhanced and the converted maize lines had almost twice the amount of lysine and tryptophan than normal maize inbreds. © 2017 Akadémiai Kiadó, Budapest.
Study of combining ability using QPM donors as testers for yield and yield traits in maize (Zea mays l.)
(Society for the Advancement of Breeding Researches in Asia and Oceania, 2015) L. Ram; R. Singh; S.K. Singh
Ten maize inbreds were crossed as female parent to 8 testers (QPM donors) as male parents to generate 80 F1 crosses. The 99 genotypes including hybrids along with their parents and check were evaluated in randomized complete block design to estimate the GCA and SCA of parents as well as crosses. Combining ability analysis revealed that significant mean square was due to line GCA for all traits except shelling per cent while tester GCA was significant only for 100 grain weight. Mean square due to SCA was significant for all traits. Variance due to SCA was greater than GCA for most of the traits and variance due to GCA was greater than SCA for 100 grain weight indicating the predominance of non-additive and additive type of gene action, respectively. The crosses CM 141 × CML 161, V335 × CML 141, V351 × CML 141 were the best hybrids based on per se performance and SCA effects. The line V335 and the testers CML 141 was found to be the best general combiner for yield and yield contributing traits. Currently, based on combining ability estimates the lines V335 and V351 are being converted into QPM lines using QPM donor CML 141 to develop local QPM hybrid. © Society for the Advancement of Breeding Research in Asia and Oceania (SABRAO) 2015.