Evaluasi Kemurnian Genetik dengan Marka Mikrosatelit dan Aplikasi Rizobakteri untuk Meningkatkan Produksi dan Mutu Fisiologis Benih Jagung Hibrida

Abstract

One effort to improve maize production is through the use of high quality maize seed. In order to assure high quality seed, it’s genetic quality must be tested. SSR markers often used in genetic studies of maize plants. Therefore SSR can be used to analyze the genetic purity of maize hybrid seed. Another effort to increase productivity and physiological quality of maize hybrid seeds is using rhizobacteria and phosphate fertilizer. The objectives of this research were 1) to determine SSR markers specific for male and female parents, 2) to know the effectiveness of SSR markers for the genetic purity testing of maize hybrid seeds, 3) to find non phytopathogenic rhizobacteria isolates capable of dissolving phosphate, producing IAA, and improving the physiological quality of seed and seedling growth of female parent of maize hybrid, 4) to assess the effect of rhizobacteria and phosphate fertilizers to increase plant growth and yield female parent of maize hybrid, 5) to investigate the effect of rhizobacteria and P fertilizer for increasing productivity and physiological quality of maize hybrid seed. This research consisted of four stages: (1) Selection of SSR primers specific for female and male parents, and testing of genetic purity of hybrid maize seed using SSR markers, (2) Characterization of rhizobacteria in producing IAA, dissolving unsoluble forms of phosphate, non phytopathogenic (hypersensitive reaction test), and improving the physiological quality of maize hybrid seed, (3) Testing the effectiveness of rhizobacteria and phosphate fertilizer on plant growth of female parent in polybag, and (4) Evaluation the effectiveness of rhizobacteria and phosphate fertilizer to increase productivity and the physiological quality of maize hybrid seed in the field. All stages of the research were conducted from April 2011 until December 2012. Results of experiment 1 showed that: 1) Out of five markers tested, three markers namely phi96100, phi328175 and phi072 produced polymorphic bands and were able to distinguish parental lines of two maize hybrid varieties. SSR marker phi96100 was specific for detection the genetic purity of cv.Bima-4 and phi072 for cv.Bima-3. While phi328175 was specific markers to both maize hybrids. The genetic purity of cv.Bima-3 and cv. Bima-4 were 97.5% and 80% respectively. Results of experiment 2 showed that from 34 rhizobacteria isolates, consisted of Actinomycetes, Bacillus spp., and Fluorescent pseudomonads, five isolates of each group having characteristic of dissolving phosphate, producing IAA, and non phytopathogenic. B28 and B46 isolates increased growth rate and vigour index of female parent seeds of hybrid maize. AB2, ATS4, B28, P14, and P31 isolates were selected based on the ability to improve the physiological seed quality of female parent and the rhizobacteria B42 based on the highest production of IAA. These isolates were then used in the field experiment. Results of experiment 3 showed that phosphate fertilizer did not effect the plant growth, weight of ear, and weight kernel per ear but rhizobacteria B42 isolate was potential to increase plant growth compared the control and other rhizobacteria. B28 isolate was potential to increase weight of ear, and weight kernel per ear. Results of the field experiment showed that at the first planting season (rainy season), application of 100 kg SP-36 ha-1 increased productivity compared to control. B42, ATS4 and P31 isolates increased number of leaves, leaf area index, and productivity of maize hybrid seeds. Trial the second planting season (dry season) showed that application of 100 kg SP-36 ha-1 increased productivity compared untreated. ATS4 rhizobacteria increased plant heigth and productivity of maize hybrid seed. Application of ATS4 isolate followed by 100 kg SP-36 ha-1 increased the percentage of good quality seeds. Rhizobacteria reduced P fertilizer 50 % from the recomendation dosage. Application of ATS4 isolate and fertilizer P 100 kg SP-36 ha-1 increased physiological quality of harvested seeds after four month storage at 21 – 25oC and 53 – 62 % RH.