SUMMARY
Heri
Kustanto. Student of the Doctoral Program, Brawijaya University of Malang. Study of Diversity, Heterosis and Molecular
Marker Assisted Selection-Phenotype
Characters In Developing of Hybrid Corn (Zea mays L.). Promoter:
Prof. Dr. Ir. Nur Basuki, Co-Promoter 1: Ir. Arifin Noor Sugiharto, M.Sc. Ph.D,
Co-Promoter 2: Prof. Dr. H. Ir. Astanto Kasno.
Success of the maize breeding
program is determined by the extent of the genetic diversities and appropriate
as well as effective selection. The genetic diversities testing are important
to find out the trait diversities among the inbred lines and uniformity within
the inbred lines. Selection in creating the maize hybrid was usually performed
by cross breeding program, such as: Line x tester analysis to find out
combining ability and heterosis between the F1 hybrid (crossbred
pairs). Heterosis is the improvement of trait appearance on the strains in
comparison with the parent concerning with the size, the growth rate, and other
characters. Heterocyst is frequently related to the genetic diversities of the
parent inbred lines and it will be found out if the segregation inbred lines
are small or homozygote and it is shown by uniformity appearance of the plant.
Along with the development of
molecular marker, which was applied on breeding program, most of the selections
in creating hybrid have applied molecular marker. The success of such molecular
marker application as Marker Assisted Selection (MAS) highly influenced by the
existed relationship between the molecular marker and the phenotype characters,
as well as its utilization in breeding program, in which such MAS requires
further study in order to obtain more accurate results and more effective.
Objectives of this research are: to find out the genetic diversities among the
inbred lines, to find out the uniformity level within the inbred lines, to find
out the heterosis value in the F1 Hybrid (crossbred pairs) and study the application
of molecular marker-fenotype characters as Marker Assisted Selection (MAS). The
proposed hypothesis in this research showed: (1) different character
appearances were observed among the inbred lines and different character
uniformity within the inbred lines, (2) There is a significant correlation
between DNA band pattern and the specific phenotype character, which can be
used as selection criteria in creating hybrid, (3) Testcross can be used to
identify a superior characters of
hybrid, (4) tester with specific and consistent inbred pairs will create higher
heterosis and (5) There is a significant relationship between the genetic
distance and the heterosis on the plant characters.
The research performed from February
to November 2011 and comprised of Experiment I and II. The experiment I
comprised of: experiment in the field and molecular analysis. The experiment in
the field was conducted in Kandat Village, Sub district of Junrejo, Batu. The
molecular analysis was done at Biotechnology Laboratory, Department of
Agronomy, Faculty of Agriculture, Brawijaya University. The experiment II was
conducted in Kajang Village, Sub district of Junrejo, Batu. The field trial in
experiment I applied 33 inbred lines and 2 comparative varieties were planted
using Randomized Complete Block Design (RCBD) with 2 replications and steps in
molecular analysis include: DNA isolation using CTAB method, which was modified
using active carbon and PVP, DNA quantity test, PCR-SSR and visualization of
the amplification result. Materials used in experiment II comprised of: 140 F1
Hybrid (crossbred pairs), 28 lines, 5 testers and 5 comparative- commercial
hybrid varieties, which were planted using RCBD with 2 replications.
Data analysis to find out the
genotype diversities of the phenotype characters in the field trial on the
experiment I applied F-test, if it was significant, and then followed by
BNT-test of 5%. The inbred lines diversities analyzed using coefficient of
variance (CV) (%). The molecular data analysis used Jaccard’s similarity
coefficient (%). The inbred lines were grouped according to the genetic
similarity through UPGMA using NTSYSpc version 2.02i. In order to find out the
Combining Ability, the experiment II applied Line x Tester analysis (Singh and
Chaudhary, 1979) and the heterocyst was calculated according to the mean of the
parent, for instance: H%= [(F1-MP)/MPx100], in which: MP= mean of
the parent. Relationship between molecular data and phenotype data were
analyzed using Spearman’s correlation coefficient (1904) (Spearman’s Rank) in (Singh and Chaundhary, 1979);
(geographyfieldwork, 20011; udel. edu.2011).
Result of the testing showed: higher
uniformity in genotype. The genetic diversities values for 18 characters in
maize out of 35 genotypes, which were tested, ranged 4 – 36%. Among those characters,
ear weight plant-1, kernel weight plant-1, diameter of
ear and grain yield had genetic diversities more than 30% and followed by
higher heritability value for about 80 – 96%. As indication of gene results
additively, these four characters showed higher genetic improvement for about
14 – 46%. Ear weight plant-1 and grain yield was the only two
character that had higher correlation coefficient with the DNA similarity
coefficient, each of its are 0.366 and 0.355. Even though number of rows ear-1
had the highest correlation coefficient (rs) between the phenotype
characters and DNA similarity coefficient (0,424), but it had lower coefficient
of genetic variation (CVG).
The mean value of heterosis for wet ear
weight plant with the entire F1 hybrid
(crossbred pair) was 65.5%. The F1 hybrid of G-38XG-T00 showed the highest heterosis
for about 212.4%. The mean value of tester parent of G-T00 showed the highest
heterosis for about 106.2%. The mean value of tester parent of G-T22 for about
62.5% and followed by higher mean value of grain yiled. The inbred line of
G-38, G-26 and G-03 with any tester
showed higher heterosis, which was more than 50%. There were 9 potential and
superior hybrid pairs of maize, which included: G-06XG-T15, G-51XG-T22,
G-49XG-T22, G-B0XG-T22, G-35XG-T22, G-38XG-T22, G-17XG-T22, G-36XG-T22, dan
G-49XG-37. The regression equation between the genetic distance and the grain
yield is: Y= 26,69X + 53,15, whereas: X is the genetic distance and Y is
heterosis (%) for character of the grain yield.
Conclusions : (1) there was higher genetic diversities
among genotypes on all characters of maize except for the maize husk weight
plant-1, (2) There was higher uniformity level of genotypes on all
characters of the maize, (3) grain yield can be used as criteria in selection
particularly in creating maize hybrid using molecular assistance, While the ear weight
plant-1 can be used as an alternative molecular marker assisted selection and plant phenotype
(4) Nine crossbred pairs can be recommended as superior-potential hybrids, such
as: G-06XG-T15,
G-51XG-T22, T22 G-49XG-, G-B0XG-T22, G-35XG-T22, G-38XG-T22, G-17XG-T22, T22-G-36XG and 49XG-G-37 had potentially bea high yielding of hybrid, (5) Inbred line of
G-38, G-26 and G-03 showed higher heterocyst value with all testers so that
they can be paired with all of the tested inbred lines, (6) tester
G-T00 consistently showed high
heterosis value, but
doesn’t followed higher
grain yield, the consistent tester of G-T22 showed higher heterosis and
followed higher grain yield, it can be used as male parent in creating hybrid.
(7) besides considering the heterosis value in creating the superior hybrid,
the genetic potency of the parent should be considered, (9) Genetic
distance is closely related to heterosis,
namely: greater genetic distance, the higher heterosis
on several characters especially the grain yield
