Jagung Manis (Zea mays var. Saccharata Sturt.) merupakan salah satu komoditas hortikultura yang populer di Indonesia. Inbreeding depression adalah fenomena penurunan vigor dan produktivitas tanaman yang disebabkan perkawinan dalam. Inbreeding depression sering diamati pada tanaman jagung yang memiliki karakteristik responsif. Tujuan dari penelitian ini adalah: 1) untuk mengetahui perbedaan karakter fenotip antara tanaman jagung manis (Zea mays saccharata Sturt var) hasil selfing dan hasil open pollinated,  2) untuk mengetahui nilai penurunan vigor tanaman jagung manis (Zea mays var. Saccharata Sturt.) hasil selfing dan open pllinated yang ditandai dengan besaran dan persentase inbreeding depression. Penelitian ini dilakukan pada Agustus-November 2013 di CV. Jogja Horti Lestari Sleman Yogyakarta dengan menggunakan metode percobaan T-test Two Sample Asuming Equals dengan 2 perlakuan. Pada perlakuan open pollinated (P1) tanaman diberi perlakuan penyerbukan terbuka hingga mencapai generasi F6 dan pada perlakuan selfing (P2) tanaman diberi perlakuan penyerbukan sendiri hingga mencapai generasi S5. Hasil penelitian menunjukkan bahwa perlakuan open pollinated (P1) berbeda nyata dengan perlakuan selfing (P2) terhadap semua karakter tanaman kecuali karakter jumlah baris biji per tongkol. Besaran penurunan vigor pada perlakuan selfing (P2) lebih besar dibandingkan dengan perlakuan open pollinated (P1) pada seluruh karakter tanaman yang diamati. Penurunan vigor ditandai dengan besarnya nilai dan persentase Inbreeding depression.

ABSTRACT

JINGGO and LABO 180.28 g and 124.23 g, respectively.

Mannose and mannooligosaccharide acted as prebiotic that consumed by probiotic bacteria. Mannanase were the second most important enzymes for the hydrolysis of hemicelluloses, beside xylanase. The objective research was to obtain eminent strains of Bacillus sp. in mannan degradation which can potentially be a probiotic candidate. The study employed a completely randomized design using four concentration levels repeated six times. Halotolerant Bacteria were isolated from mangrove ecosystem at Hanura beach, Teluk Pandan, Pesawaran District in Lampung Province. They are grown on the sea water complete agar media. Mannan degradation isolates were then characterized to determine their character with a variety of tests, including resistance to pH, salt, and metal ions, pathogenicity, and determination of mannanase production duration. Thirty strains are found to grow at 3-6% salt content, and 9 of them have mannanolytic activity. They grow optimally at pH 7-10. Seven isolates were proven to be positively hydrolyzed blood agar in the pathogenicity test. The addition of Iron (III) Chloride increased the enzyme activity by 11.12% in IBK3 isolates at 96 hours of cultivation period which was 0.05 UmL-1. It acted as cofactors of enzymatic reactions. Strains Bacillus sp., were able to degrade mannan substrate. It quantified using Index of mannanolytic. Strain IBK3 has the highest index of mannanolytic activity as much as 10.74. Their ability to grow in salt media indicated that they were halotolerant. They were more likely to live at base rather than acid habitat. Only IBK3 and ID2K1 showed non-pathogenic isolates. Only FeCl 3 addition has proven to rise up enzymatic activity.

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