<p>Information on genetic diversity, homozygosity, drought stress and low N tolerance of maize inbred line are useful for parental selection in developing maize varieties tolerant to drought and low N. The objectives of this study were (a) selection for homozygoes lines and analysis of genetic diversity among 51 maize inbred lines applying simple sequence repeats (SSRs) using thirty six markers (b) selection for inbred lines (homozygosity over 80%) for drought and low nitrogen (N) tolerance. Experiment was conducted using split-split plots design with three replications. Water treatments were as the main plots (well-watered and drought stress conditions), subplots were nitrogen fertilization at rate of 75 and 150 kg N/ha and the sub-sub plots were 51 inbred lines. The results showed that there were broad ranges of genetic variability among inbred lines with genetic similarity coefficient values ranging from 0.22 to 0.87 and polymorphism information content average was 0.57. Thirty inbreds having homozygosity over 80% were spread into six heterotic groups. Drought tolerance inbreds were in heterotic groups C and F, namely DTPYC9-F46-3-9-1-1-B and 1044-30, the drought medium tolerance in heterotic group A and B, namely CML 161/NEI 9008 and MR 14. Inbred for low-N fertility tolerance was in the heterotic group D namely G20133077, while medium tolerance to low-N fertility inbreds were in heterotic group A, B, C, D, and F, and they were CML 161/NEI 9008, CY 11, CY 15, CY 6, CLRCY039, Nei9008, DTPYC9-F46-1-2-1-2-B, G2013627, G2013649, 1044-30. Inbreds tolerance to both medium drought and to low-N fertility were in heterotic group C and F they were DTPYC9-F46-1-2-1-2-B and 1044-30. Inbred lines of maize tolerant to drought and to low-N fertility can be used as parent to develop hybrid or synthetic varieties, posessing stress tolerances, by cross recombination between heterotic groups.</p>

Abstract. The demands for alternative sources of energy are currently growing because people now are more aware of the many negative impacts fossil fuel gives to the environment. Plant based renewable energy provides potential sources of energy with advantages of cleaner fuel effect and capability of integration with food crop production. Sorghum have been considered to be a highly potential source of food, feed and fuel, especially sweet stalk sorghum that posses both functions as source of food from its grain and fuel made from its stalk juice. Sorghum varieties are well known to have excellent adaptability in marginal areas, especially drought prone areas where other food crops are unable to thrive. The current paper aimed to share ongoing research on many functional uses of sweet stalk sorghum varieties released at Indonesian Cereals Research Institute (ICERI). Among many varieties that had been released were two sweet stalk sorghum varieties SUPER-1 and SUPER-2 released in 2013 that stands out in biomass yield and bioethanol production. Based on various researches conducted at different location and planting season, yield potential of biomass ranged at 30 -40 t/ha with higher yield occurred during dry season. Stalk juice sugar content in brix were found to be higher in dry season ranged at 13.6 % to 18.4 %, and the amount of juice stalk was obtained at about 30-50 % from total biomass yield. Furthermore, bioethanol production from stalk juice after fermentation was at the range of 8 to 10 % from total stalk juice volume. Modification of processing equipment of bioethanol have also been carried out and was able to increased the concentration of ethanol being distilled from 85% -92% to 90% -95%. Another result obtained was able to decreased fermentation time from 14-21 days to 6-10 days. Furthermore, the yield of ethanol from juice was also from an average of 4.95% to 6.75%.

Maize breeding population with a wide genetic diversity is required to develop superior drought tolerant varieties. The objective of this research was to obtain information on genetic diversity, heritability value and grain yield performance, yield components and agronomic traits of maize genotypes derived from top cross under severe drought stress. One hundred and fifty maize genotypes derived from top cross and four hybrids maize as check varieties, were tested in Probolinggo, East Java, and Gowa, South Sulawesi during dry season of 2013. Factorial randomized block design with two replications was used in thisexperiment. Each hybrid was grown in two rows of 5 m length plot, one plant per hill spaced 70 cm between rows and 20 cm within row. Results showed that top cross hybrids had significantly different responses to drought stress. Broad sense heritability, value of silking, number grain-rows per ear, and shelling percentage were high. Heritability estimates for of anthesis, anthesis-silking interval, plant height, ear height, weight and ear performance, ear length, 1000 seeds weight and grain each yield were intermediate. The 20 best hybrids based on the highest grain yield, consisted of 17 genotypes with good combining ability with P21, 2 genotypes had good combining ability with Bima 11 and only one genotype had good combining ability with both the top cross parents, (P21 and Bima 11). Grain yield of 20 top cross hybrids in Probolinggo ranged from 4.8 t/ha to 6.7 t/ha significantly higher than that of tester varieties, while yields in Gowa ranged from 4.5 t/ha-6.7 t/ha. Only 4 tested hybrids significantly outyielded the four tester varieties. For the purpose of further selection, determining of the best S1 genotype should be done per location to overcome large environmental effects.

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