Study on the vegetative propagation of guava (Psidium guajava L.) Through air and stool layering” Mr

ABSTRACT
The experiment entitled “EVALUATION OF PRE AND POST EMERGENCE HERBICIDES FOR THEIR EFFICACY AND SELECTIVITY IN ONION AND TOMATO CROPS” wasconducted at the College farm of Horticultural college and Research Institute, Venkataramannagudem, W.G (dt), A.P during the year 2011-12 and 2012-13.

In both Onion and Tomato crops weed management practices exerted their significant effect on density of weeds viz., grasses, sedges, and BLWs and Total weeds, dry matter of weeds at various stages of crop growth.Theseattributes found to be maximum with T10 (unweedy check),while T9 (Weed free-hand weeding at 20, 40 and 60 DAT) registered lower values followed by Pre emergence herbicides either Pendimethalin @ 0.75 kg a.i / ha or Oxyfluorfen @ 0.125 kg a.i / ha coupled with Quizalofop ethyl @ 75 g a.i / ha found to be effective in decreasing the weed population and dry matter of weeds to a greater extent.

Highest weed control efficiency and lowest weed index values were observed with T9 (Weed free-hand weeding at 20, 40 and 60 DAT) followed by chemical weed control (Pendimethalin @ 0.75 kg a.i / ha as PEor Oxyfluorfen @ 0.125 kg a.i / ha as PE + Quizalofop ethyl @ 75 g a.i / ha as POE) treatments.

Maximum depletion of NPK by the weeds was found in T10 (unweedy check) during various stages of crop growth. Chemical weed control (Pendimethalin @ 0.75 kg a.i / ha as PE or Oxyfluorfen @ 0.125 kg a.i / ha as PE combined with Quizalofop ethyl @ 75 g a.i / ha as POE) was found better in reduction of NPK removal by the weeds next to T9 (Weed free-hand weeding at 20, 40 and 60 DAT).

In Onion growth attributes viz., Number of leaves per plant, LAI, Plant dry matter and yield attributing characters viz., average bulb weight, bulb diameter, Neck diameter, bulb height are found to be higher with application of Pendimethalin @ 0.75 kg a.i / ha as PE in conjunction with Quizalofop ethyl @ 75 g a.i / ha as POE next to T9 (Weed free-hand weeding at 20, 40 and 60 DAT).

In Tomato chemical weed control treatments either Oxyfluorfen @ 0.125 kg a.i / ha or Pendimethalin @ 0.75 kg a.i / ha coupled with Quizalofop ethyl @ 75 g a.i / ha as POE registered maximum values for growth parameters viz., plant height, number of branches per plant, LAI, plant dry matter and yield attributes viz., number of fruits per plant, fruit yield per plant, average fruit weight and fruit yield next to T9 (Weed free-hand weeding at 20, 40 and 60 DAT).

The nutrient uptake (NPK) by the onion and tomato crops were significantly highest with T9 (Weed free-hand weeding at 20, 40 and 60 DAT) followed by chemical weed control treatments.

Quality parameters viz., ascorbic acid in tomato, total soluble solids (TSS), sprouting (%) and rotting (%) in onion were not affected due to herbicide application.

In both Onion and Tomato crops Pendimethalin @ 0.75 kg a.i / ha or Oxyfluorfen @ 0.125 kg a.i / ha in combination with Quizalofop ethyl @ 75 g a.i / ha as POE gave maximum benefit cost ratio over hand weeding at 20,40 and 60 DAT. Though Imazethapyr @ 60 g ai ha ^-1 as POE was effective in controlling the weeds as evident from weed dry matter but found to be highly toxic to the Onion and Tomato.

2. 
   “Genetic diversity, heterosis, combining ability and stability analysis for yield and yield components in purple brinjal”- V. Chaitanya.
   

ABSTRACT

The present investigation entitled “Genetic diversity, heterosis, combining ability and stability analysis for yield and yield components in purple brinjal” was undertaken to identify diverse parents, study the combining ability, heterosis and stability of experimental hybrids for yield and yield components in brinjal.

During rabi 2012, fifty one genotypes were evaluated for genetic diversity at Vegetable Research Station, Dr.Y.S.R. Horticultural University, Rajendranagar, Hyderabad. On the basis of the mean performance of the genotypes among traits studied, the following were identified as promising lines for further crop improvement in brinjal viz., A₁₄ (IC-281104), A₄₃ (IC-439263), A₄₄ (IC-090084) and A₄₇ (IC-090084-2)_.

Based on genetic variability studies, high PCV and GCV and high heritability coupled with high genetic advance as per cent of mean were recorded for fruit length, fruit width, average fruit weight, total number of fruits per plant, number of marketable fruits per plant, total yield per plant, marketable yield per plant and ascorbic acid content indicating the existence of wider genetic variability for these traits in the genotypes under study.

The traits ascorbic acid content, average fruit weight and total number of fruits per plant were the major contributors towards divergence. Based on Mahalanobis D² analysis the fifty one genotypes were grouped in to eight clusters. The pattern of distribution of genotypes into various clusters revealed that there was no relationship between geographical distribution and genetic diversity. Greater genetic divergence was between clusters V and VIII, suggested exploitation of these two clusters by intermating genotypes in a definite breeding designs to explore the fullest range of heterosis and to realize good recombinant lines. Based on this study horticulturally superior genotypes viz., A₁₄ IC-281104, A₂ IC-021621, A₂₂ IC-127024, A₄₇ IC-090084-2, A₄₈ IC-090084-4, A₃₆ IC-090783-3 and A₃ IC-23771 were selected for hybridization programme as they were expected to produce high heterotic crosses.

Correlation and path coefficient analysis studies revealed positive correlation and direct effect on marketable fruit yield per plant exhibited through fruit length, average fruit weight, total number of fruits per plant and number of marketable fruits per plant.

Seven parental lines thus identified were crossed in half diallel fashion during summer, 2013. The resultant twenty one crosses along with seven parents and two checks (Chhaya and Utkarsha) were evaluated in three seasons viz., kharif, rabi and summer, 2013-14 for combining ability, heterosis and stability studies so as to identify the promising F₁ hybrids with high productivity, good fruit quality and wide adaptability for commercial exploitation.

The pooled analysis of variance for combining ability analysis revealed significant differences due to environments, parents, hybrids and various interactions indicating the existence of wider variability in the material under studied. The ratios of GCA / SCA variances revealed that non-additive gene action was predominant in the inheritance of all the characters except fruit length, fruit width and average fruit weight. Hence heterosis breeding is ideal to improve these traits.

The gca effects of the parents in pooled analysis revealed that P₂ IC-021621 was found to be promising general combiner for marketable fruit yield per plant and other traits and P₆ (IC-090783-3) was a good general combiner for earliness attributes whereas P₁ (IC-281104) was a good general combiner for days to last fruit harvest and less incidence of fruit and shoot borer infestation on fruits. Based on significant sca effects, five hybrids viz., C₃ (IC-281104× IC-090084-2), C₁₁ (IC-021621× IC-23771), C₁₃ (IC-127024 × IC-090084-4), C₁₆ (IC-090084-2× IC-090084-4) and C₂₁ (IC-090783-3× IC-23771) were identified as promising for marketable fruit yield per plant and other yield contributing characters.

Based on per se performance, sca effects, heterobeltiosis and standard heterosis for yield and its attributes in pooled analysis, five cross combinations viz., C₃ (IC-281104× IC-090084-2), C₁₁ (IC-021621× IC-23771), C₁₃ (IC-127024 × IC-090084-4), C₁₆ (IC-090084-2 × IC-090084-4) and C₂₁ (IC-090783-3 × IC-23771) proved to be superior for yield and yield contributing characters.

Among the seasons, rabi was found to be the best season for growing brinjal as observed from the highest positive environmental indices for most of the growth and yield attributing characters besides manifestation of desirably negative environmental index for fruit and shoot borer infestation on fruits. The hybrids C₃ (IC-281104× IC-090084-2), C₁₁(IC-021621× IC-23771), C₁₃ (IC-127024 × IC-090084-4) and C₂₁ (IC-090783-3 × IC-23771) are identified as stable with desirable sca effects, heterosis and per se performance for marketable yield per plant and other important attributes. These hybrids may be further tested over locations, seasons and years and recommended for commercial release.